Question

The perimeter of a square is 20 units. One side is the square root of a+10. What is the value of a?

Answer 1

there are 4 edges that make up a square
adding these edges we get 20
each edge has equal length
so we have L+L+L+L=20

if L=sqrt(a+10) then what is a

you have 4L=20 since (L+L+L+L=4L)
just replace L with sqrt{a+10) and solve for a

Answer 2

I have \[\sqrt{a+10}=5\]
\[\sqrt{a+10}^{2}=5^2\]
a+10=25
a=15 ?

Answer 3

looks good :)