If 28% of a sum is $100.80, what is the sum?

Linet passes through (4.5) and is perpendicular to the line shown on the condirate grid. what is the equation of line t in standard form?

Does anyone know how to do geometryme with this problem

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?