A cake measures 18 centimeters in diameter. Find how much room there is to spread frosting on the top of the cake. Complete the answer sentence. You may consider writing your answer to the hundredths place and using the calculator to help you solve.

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?