Some one pls help me I’m not very good at math

Which math sentence can be used to determine if the triangle is a right triangle?

Calculate the missing value. round the answer to on decimal place. start with 70, increase it by 21%, and end up with

The triangle shown has a hypotenuse with a length of 13 feet. the measure of angle a is 20 degrees. and the measure of angle b is 70 degrees. which of the following is closest to the length, in feet, of line segment ac? no need to use a calculator to find the trig numbers. each function is listed below. 4.4 5 12.2 35.7