Using the formulas to find its length =
P= 2 ( l + w )
d= w² + l²
There are 2 solutions for,
l = P / 4 + 1 / 4 √8d² - p²
= 39.2 / 4 + 1 / 4 × √8 × 14² - 39²
= 11. 2 km answer.
Using the formula to find its width =
w = p / 2 - l
= 39.2 / 2 - 11.2
= 8.4 km answer.
≈ the length of a rectangle is 11.2 km and the width is 8.4 km