Question 254917
So one side is 3 meter and the other is 10meters
If you divide the rectangle by a diagonal, you now have a triangle..but the height and width of the triangle are the same as the rectangle

in a triangle  a^2 + b^2 = c^2  with c being the length of the diagonal
so:  side a = 3 meters  side b = 10

so 3^2 + 10^2 = c^2

9 + 100 = c^2
109 = c^2   take the square root of both sides
10.4 = c

hope this helps