How do you find the third side of a triangle if you already know two of its sides

Two sides of the triangle each have length of 5. All of the following could be the length of the third side EXCEPT
A) 1 B) 3 C) 4 D) square root of 50 (approximately 7.07) E) 10

I know that D couldn't be the answer because it can be it. But I don't know which one can't....Help

A, B, C and D could be possible answers.

E cannot be, because the length of the other side of the isoceles triangle

must be less than the sum of the other two sides. If it were 10, it would not be a triangle,

but a line segment.

ok this is simple u hav to use the Pythagorean Theorem, it a(squared) + b(squared) = c(squared). u know that 2 angles are both 5 its just 25 + 25 = c^2
50=c^2
then u figure out the square root of 50 and c^2 to get:
in this case D
but in shortest terms it would be 5, square root of 2

D) can be an answer, if it's a right triangle.

a^2+b^2=c^2
5^2+5^2=c^2
25+25=50

Yep, looks like E is the answer.

If you try to draw a triangle with sides 5, 5, 10 you will get a straight line, not a triangle.