Question

Plsss help me! What is the lenght of AB

Answer 1

Answer:

Step-by-step explanation:

Because angles A and B are the same, line segments AB and BC are the same.  This means you can use the same variable for both in the Pythagorean theorem.

x²+x²=20²

2x²=400

x²=200

x=√200

x=14.1421356237

Answer 2

Answer:

x = 10$\sqrt{2}$

Step-by-step explanation:

this is a 45-45-90° Δ and the leg to hypotenuse ratio is always 1 : $\sqrt{2}$

so we can set up a proportion:

20 / $\sqrt{2}$ = x / 1

cross-multiply:

$\sqrt{2}$x = 20

x = 20 / $\sqrt{2}$, which simplifies to 10$\sqrt{2}$ if you rationalize the denominator