Bill is building a model of a square pyramid for a class project. the side length of the square base is 10 inches and the slant height of the pyramid is 15 inches. what is the surface area of the model pyramid?

Harry owes the bank money. to repay his debt, he paid $150 back to the bank each month. after 10 months, his remaining debt was $6900. what was the original amount of harry's debt? how long did it take harry to pay back his entire debt?