The outer diameter of a metal pipe is 2.84 cm and the inner diameter is 1.94 cm. what is the thickness of the pipe

For the equations below which statement is true ?

One side of a rectangle is 7 feet shorter than seven times the other side. find the length of the shorter side if we also know that the perimeter of the rectangle is 306 feet.

Calculate the density of benzene if 300ml of it weighs 263g. a. 0.88 g/ml b. 1.14 g/ml c. 78,900 g/ml d. 37 g/ml