Hello!
To find the base length you use the Pythagorean Theorem
[tex]a^{2} + b^{2} = c^{2} [/tex]
c is the slant height
a is half the base length
b is the height
Put in the values you know
[tex] 10^{2} + 10^{2} = c^{2} [/tex]
Square the numbers
[tex]100 + 100 = c^{2} [/tex]
Add
[tex]200 = c^{2} [/tex]
Take the square root of both sides
[tex]c = \sqrt{200} [/tex]
Simplify
[tex]c = 10 \sqrt{2} [/tex]
Hope this helps!
