The answer for A would be 8.5 because if you use a^2+b^2=c^2 you would have 12^2 which equals 144 and you would divide that by two to get 72 and then take the square root to find the side length
The answer for be would be 45 because the sum of all angles in a triangle is 180 and you already know one is 90 and 180-90=90 and because this is an isosceles triangle you know the two bottom angles are equal so 90/2=45
