Numbers 20 - 22 please

If the measure of xyz is 81 what is the measure of yz

What is the missing constant term in the perfect square that starts with x^2 -20x

Television sizes are based on the length of the diagonal of the television's rectangular screen. so, for example, a 70-inch television is a television having a diagonal screen length of 70 inches. if a 70 inch television's diagonal forms a 29°angle with the base of the screen, what is the vertical height (1) of the screen to the nearest inch? 70 inhin