Circumference and Area of this circle please

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

What is the solution set of the quadratic inequality x^2-5< or equal to 0

Lin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. she knows that the total cost to download 3 videos was $12. her work to find the equation is shown below. joylin’s work step 1 k= 3/12= 0.25 step 2 y= 0.25x where did joylin make her first error?