30 yd wide and 50 yd long find the length of the diagonal

It's the same as finding the hypothenuse of a right triangle. Let c be the hypothenuse.

30 squared+ 50 squared= c squared.

900+ 2500= c squared
3400= c squared

Then find the square root of 3400 and that will equal c.

So, depending in what form the teacher was the answer. The answer will be square root of 3400 ft squared or 58.3 ft squared.