Please help me please

Step-by-step explanation:

A comment: If the angles of a triangle (on a flat surface) always add to 180°, then our missing angle must be 180 - 90 - 60 = 30°. 30 is half of 60, and that fact makes it very tempting to try and make this triangle "whole" by stitching two copies of it together. After doing this, we get a triangle with three 60° angles: an equilateral triangle. If all sides of the triangle must be 20, and we put two equal sized lengths together to find create the bottom length, than each of those lengths must be half of 20, or 10.

And with two sides of our right triangle, we can find our third using the Pythagorean theorem:

step-by-step explanation:

the true ones are a b and d