Calculating Triangle Side Length with Known Angles and Radius

[BrentK]

Hi there.
Can someone tell me how to calculate the length of "a", shown in these drawings?
"r" is the radius of the corner, so these 2 sides have the same length.
"C" is 90 deg
angle "B" is known (the angle of the corner)

Here are the diagrams. First example 45 degree corner, second example 75 deg corner.

Many thanks in advance for your help! (Nerd) ;)

View attachment 8683

View attachment 8684

 

[Opalg]

If I understand the problem correctly, the answer is $a = r\tan\bigl(\frac12B\bigr)$.

 

[BrentK]

Thanks Opalg!
That works perfectly!
So easy... I was trying to hard (Dull)