How is adding 6+3 like adding 60+30

Koji is installing a rectangular window in an office building. the window is 823 feet wide and 534 feet high. the formula for the area of a rectangle is a=bh. what is the area of the window? enter your answer as a mixed number in simplest form in the box. $$ ft2

Which of the following circles have their centers on the x-axis? check all that apply.

Yvaries directly as x. y =90 when x=6. find y when x=13