Length = 36 in
width = 24 in
Let the diagonal be be x
Using pythagoras theorem;
opposite² + adjacent² = hypotenuse²
From the figure above;
adjacent = 24
opposite = 36
hypotenuse=x
applying the theorem;
36² + 24² = x²
1296 + 576 = x²
1872 = x²
Take the square root of both-side
√1872 = √ x²
43.2667 = x
x ≈ 43 in
Hence, the diagonal of the frame is 43 in