Follow along this GRE geometry question!

[@ReeRee_Donita]

Got it right. Angle AOB could be 88-89 degrees. Usually if there’s no right angle indicated, it’s not a right angle triangle, even if it appears to be.

[@applepeel1662]

Woah my brain automatically went to 90 degree triangle. Actually useful, thank you! (Cue the song with the lyric "im only human afterall")

[@MagooshGRE]

😎 🎶

[@suhailahameds4526]

​@minakumari7552woah me too man😅

[@aaliz110]

This is isosceles right triangle angle, so AB length is definitely greater in measurement, we can determine it. Option B is correct.

[@abbeyavegno7130]

how can you assume it’s an isosceles?

[@manoz.881]

@@abbeyavegno7130 because AO and OB are equal being radius of circle

[@ReeRee_Donita]

It’s not an isosceles. They would indicate it on the triangle with the equal lines. If you don’t see it, never assume it is. Same goes with the equilateral triangle.

[@manoz.881]

@@ReeRee_Donita that's an isosceles triangle if not then prove it

[@farrisfathallah2862]

⁠@@manoz.881It’s 100% and isosceles triangle. However that doesn’t take away from the fact that we can’t make an assumption on the length of AB. AO and OB are exactly equal in length given O is the center of the triangle.

[@rosegold5720]

so basically, question everything you learned bc the test isn't testing your math skills but your cynicism 😂 (all jokes aside, this thought pattern helped me with the act so i'll stick to it!)

[@MagooshGRE]

😅 Love GRE jokes! Be sure to check out our helpful article about what we CAN assume on GRE diagrams here: magoosh.zendesk.com/hc/en-us/articles/115000061886-What-can-I-assume-is-true-on-GRE-diagrams-

[@paiguy3624]

Good tips😂😂

[@onward2727]

MAN. It’s ridiculous smh So yeah, you have to look for (and KNOW what to look for) explicit details like the little square thing / right angle sign in a triangle indicating it’s a right angle & right triangle And if it’s not there, something you also have to remember and notice, then you cannot assume it is a right angle & right triangle

[@brenforprez1993]

Isn’t it fixed? Why would we assume B moves somewhere else if it’s already plotted on the circle?

[@MagooshGRE]

B is fixed. The video is just showing that we don't know what the actual angle size is. So, the angle could be more or less than 90 degrees. Remember, we cannot trust the look of GRE diagrams, so we can't assume it's a 90 degree angle there. More info here: magoosh.zendesk.com/hc/en-us/articles/115000061886-What-can-I-assume-is-true-on-GRE-diagrams- 🙂

[@tech-guide7894]

Inscribed angle 90deg

[@SatiaPutra]

B is greater because is hypotenuse of the triangle

[@omoa2]

I read somewhere that geometry questions rearly have D as an option

[@Buna5689]

😂

[@Deep.ramgarhia]

A and b are equal

[@maurocometrue]

Great exercise. Quite basic, but super insightful!

[@MagooshGRE]

Thank you!

[@christiandjami1965]

Why isn't it C? If O is stationary, then the length to O from any point should be the same, no? Assuming it's a perfect circle.

[@haquefareed3175]

The straight line depicts the 180 angle

[@MagooshGRE]

Sure, it depicts a 180 degree angle, but that doesn't give us any additional information that we need to solve.

[@sugoi5240]

Oof this is different from what we are usually asked here. Gotta practice for this exam seperately lmao

[@mdmorshedalam253]

D is the correct answer. Because it says O is the center. It didn’t say the angle

[@MagooshGRE]

🙌

[@ReeRee_Donita]

Exactly

[@diyorbeknabiyev379]

B is greater because sqrt(r*r+r*r)= sqrt(2)*r

[@user-rm1qy7hh4m]

Oooh I might mistake if I didn’t check this video. Thanks

[@MagooshGRE]

Glad we could help!

[@RichardEzaka]

the correct answer is (C) A & B are equal.

[@bonnie7643]

Are A and B not points on the circle? Because if they are then AO and AB are both radii

[@MagooshGRE]

Yes, they are on the circle and AO and OB are the radii! But the question asks us to compare AO and AB, which is different!

[@davidcrabtree7945]

@@MagooshGRE if they’re both radii, then doesn’t AO = OB? If AO = OB, then the triangle must be 45-45-90. No?

[@doords]

@@davidcrabtree7945 Only if AOB is 90 degrees, which it doesnt have to be. AOB might be 45 degrees or 120 degrees

[@tungo9869]

Easy! Every result must be base on the evidences.

[@hamzanawazawan]

Aob is a right triangle, so ab is greater tha ao

[@MagooshGRE]

We can't assume that there is a right angle unless we're told there is one. Keep that in mind for the GRE!

[@swayamswarupbiswal3850]

​@@MagooshGREoo yeah i forgot about that😮😮‍💨, thanks for the explanation

[@pranavtiwari125]

@@oyewooluwaseun7762 bro u cannot assume....if it is a right angle then the diagram has to depict and denote the diagram with a right angle sign in the diagram....hence data is insufficient so the answer is D

[@aksheshpatel4588]

​@@MagooshGREBut as we can see AB is hypotenuse of triangle and hypotenuse is the longest side of any two others .so how is it satisfied?

[@bhargavi7474]

@@oyewooluwaseun7762it could be an 89.9 degree angle. You never know until they say so.

[@karlosleklerk9065]

Mock test nya dimana ya??? 😅

[@akash-ui9uf]

It is an isocelus triangle so can a or b be equal?

[@MagooshGRE]

We don't know if it's an isosceles triangle or not. We don't have information about the angle or the sides.

[@roshini7369]

​@@MagooshGREbut OA = OB right since both are radius of the circle? So it is an isosceles triangle right

[@NasirAli-ly5io]

As it say 0 is at center, and distance from center to any point on border of circle is the same, so should it not be C ?

[@doords]

@@NasirAli-ly5ioAO is the radius, AB is not the radius. So they are not the same

[@liad0x]

What? But the line is literally drawn on there??

[@MagooshGRE]

Here, we don't know the size of the angle AOB. So, it doesn't help us understand the size of line AB at all.

[@minhquan5005]

Can someone explain to me why is D? we clearly see that angle AOB is largest(obtuse angle) and angle BAO/ABO(acute angle) as shown in the diagram. AB(opposite to angle AOB) must be the longest in triangle AOB.

[@satabdeesahoo]

she explained it. although it looks from the figure that AB is largest we cant say about it as the angle aob is not stated. so it cannot be determined

[@christiandjami1965]

@@satabdeesahoo So if there's no indication of any sorts, we assume that the circle is not perfect circle and the angle is not 90 degree?

[@doords]

@@christiandjami1965 circle is perfect circle, thats given. Angle is not 90 degrees.

[@shyleshs2322]

AO is greater than AB The reason is AO is the radius and AB's length should be lesser than the radius

[@MagooshGRE]

There is no rule that says AB has to be less than the radius.

[@manishbusinesslancer3093]

We want more of this ❤

[@MagooshGRE]

You got it!

[@th.rohitsinghrajput]

In triangle we know that AB^2 = AO^2 + BO^2 We have AO = BO=a in circle AB^2 = 2a^2 AB = 1.42a AB is greater then AO

[@MagooshGRE]

Nice!

[@Reptar4000]

Incorrect

[@rahulchaudharyfisheries9730]

It would have been right, if question had mentioned right angle triangle!!

[@parimalavasireddy8192]

Ans is b Oa=ob (radius) AB= 1.414 OA

[@MagooshGRE]

Since we don't know the size of any of the angles (remember, we cannot assume right angles on the GRE), then we can't calculate the length of AB.

[@minhquan5005]

Doesn't need to know if angle AOB right or not. It's obvious that angle AOB is the largest angle in triangle AOB. So AB (opposite to angle AOB) must be the longest line in triangle AOB.

[@vivamsi8208]

B

[@MagooshGRE]

The correct answer is D, as shown in the video. Be sure to review it! 🙂

[@harmxytips9009]

More info please

[@MagooshGRE]

We don't know the size of any of the angles here (as the video states, we cannot assume right angles on the GRE unless we're told there is one or the right angle symbol is shown), then we can't calculate the length of AB.

[@ahsanraja230]

B is greater

[@lakavathdinesh899]

C is correct

[@MagooshGRE]

As we show, D is the right answer. That's because since we don't know the size of any of the angles here (we cannot assume right angles on the GRE unless we're told there is one or the right angle symbol is shown), then we can't calculate the length of AB.

[@me__vinay5917]

B

[@boburjonahmedov7128]

D

[@hirenmoradiya9866]

Cant determined the length of two sides

[@MagooshGRE]

✅

[@hugoedelarosa]

There is no little square symbol saying there’s a 90 degree angle in this triangle.

[@MagooshGRE]

You're right! That's why we can't assume it is 90 degrees.