Question

Plsss help me! What is the lenght of AB

Answer 1

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

x = 10
`√(2)`

Explanation:

this is a 45-45-90° Δ and the leg to hypotenuse ratio is always 1 :
`√(2)`

so we can set up a proportion:

20 /
`√(2)` = x / 1

cross-multiply:

`√(2)`x = 20

x = 20 /
`√(2)`, which simplifies to 10
`√(2)` if you rationalize the denominator