How to measure roof rafters including the pitch and bird's mouth (seat) cuts (captioned)

Once you know the length of the rafter, how do you correctly mark the angle to cut where the rafter meets the ridge (top) board? And what about where the rafter rests on the outside wall's top plate - how to calculate that seat cut, aka bird's mouth cut?
This is the last of 4 videos in this series.

[@abajhalghamdi9219]

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[@kelleytran7399]

great video. I watched several video but I couldn't understand how to calculate bird mouth cut. you did a great job of explaining this. Thx

[@automaster209]

Awesome. I had to watch twice too. Very good video.

[@pinarellolimoncello]

Good video, I like the accuracy of the 3 and half inch part.

[@abajhalghamdi9219]

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[@islandmystify]

Very well done gonna have to watch twice!

[@kristiwirrenga8553]

Thank you! Very well presented and informative. I learned a lot.

[@motodm4907]

Very helpful thank you

[@bernardoespinal6608]

Good information

[@rustywatts9358]

damn that's a lot of adding and stuff to remember

[@jimreagan970]

Good video nice job!

[@tomknud]

net video, thanks