Jesse D. answered 09/22/19
Patient and Experienced Mathematics and Spanish Tutor
To find the length and width in decimal form, use your calculator to multiply 2 times root 7 and 10 times root 7:
2 * √7 = 5.3
10 * √7 = 26.5
If the owner puts a diagonal fence up in her yard, she has just created two right triangles of identical dimensions. This means we can use the Pythagorean theorem (a2+b2=c2) to find the length of the diagonal. The diagonal of a right triangle is always the c while the legs are the a and b:
a2+b2=c2
(2√7)2+(10√7)2=c2
4*7 + 100 * 7 = c2
28 + 700 = c2
√728 = √c2
c = 2√182 decimal form = 27.0 yards
I'm assuming the old fencing needing replaced is the length and width and not the diagonal. So we just need to find the perimeter of the old fence using 2w + 2l:
2w + 2l
2(2√7 ) + 2(10√7) = 4√7 + 20√7 = 24√7 decimal form = 24*√7 = 63.5 yards
If you have questions please don't hesitate to leave me a comment!

Jesse D.
09/22/19
Carly F.
I totally understand this! thank you so much for such a fast and accurate response!09/22/19