math
posted by Jane .
A gardener is mowing a 20 yardby40 yd rectangular pasture using a diagonal pattern. He mows from one corner of the pasture to the corner diagonally opposite. What is the length of this pass with the mower? Give your answer in simplified form.
Please explain to me how to solve. Thanks.

Use the Pythagorean Theorem.
a^2 + b^2 = c^2
20^2 + 40^2 = c^2
400 + 1600 = c^2
2000 = c^2
44.7 = c