Since this is a right triangle, we know we have to use the Pythagorean Theorem: A² + B² = C² , where A and B = the legs of the triangle (which are shorter than the hypotenuse) and C = the hypotenuse.
In this isosceles triangle, A = B (because the legs are the same size) and C is 10cm longer than A and B.
Thus we get the following,
A = x
B = x
C = x + 10
We simply plug in these variables into the equation and solve for x:
x² + x² = (x+10)²
2x² = x² + 20x + 100
x² - 20x - 100 = 0
We solve for x by completing the square:
(x² - 20x + 100) - 100 = 100
(x-10)² -100 = 100
(x-10)² = 200
x - 10 = √(200)
x - 10 = 10 √2
x = 10 + 10√2 = 24
Finally,
A ≈ 24 (or 10 + 10√2)
B ≈ 24 (or 10 + 10√2)
C ≈ 24 + 10 ≈ 34 (or 10 + 10√2 + 10 = 20 + 10√2)