How to write one billion in standard form

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction

Which geometric principle is used to justify the construction below?

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