Question 360893
Complementary angles: Two angles who, combined, amount to 90 degrees. 

So let's call one of the two angles x. In your question it says "half the second angle", which would be represented as 1/2(90-x). 

Therefore: x + 1/2(90-x) = 77.5

And then you just solve from there. 

x + 45 - 1/2x = 77.5

1 1/2x + 45 = 77.5

Just pick up where I left off. Hope this helps!

~IW4D