A can of beans has surface area 381cm^2. It's height is 20cm. What is the radius of the circular top?

Question

answer this question For me please

Answer 1

SA=lateral area plus top circle area plus bottom circle area

SA=C*h+2∏r^2

SA=2(∏)(r)(h)+2(∏)(r^2)

381=2(3.14159)(r)(20)+2(3.14159)(r^2)

divide both sides by 2(3.14159)=6.28318

60.63808=20r+r^2

r^2+20r-60.63808=0

use the quadratic formula

[-20±√(400+242.5523)]/2

[-20±√642.5523]/2

[-20±25.3486]/2

5.3486/2

2.6742 cm=r  (answer)