MATH trigonometry
posted by sara .
in an isosceles triangle the vertex angle measures 90 degrees and the length of each congruent leg is 5√2. whats the length of the base?

Isn't the base the hypotenuse of a rightangled triangle?
so h^2 = (5√2)^ + (5√2)^2
= ....... 
20?

How did you come up with that?

i put it into the calculator and i got 20

You should not need a calculator.
h^2 = (5√2)^ + (5√2)^2
= 50 + 50
= 100
h = √100 = 10 
oohh okay i get it now
thank you soo muchh!