Ineed to find the volume of the cube using v=l*w*h

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

Simplify. (-2)^-3 a. -8 b. -1/8 c. 1/8 d. 8

Precalculus question, image attached.