Pls help me i need help asap 30!! points pls help on all 4 questions

Nikolas calculated the volume of the prism. his work is shown below.

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?

Find the combined area of the triangles. click on the answer until the correct answer is showing.possible answers: a = 4 pi - 8a = 9 pi - 9/2 √3a = 16/3 pia = 16a = 27 pi