Magnifying mirror produces upright virtual image 2.5 time as high as an object 24 cm in front of it. Radius?

Question

Find the Radius of Curvature

Answer 1

Somebody is going to have to check my math (and proper equation usage), it has been a long time since I took physics.

given:

m = y'/y = -s'/s

1/s + 1/s' = 2/R

m = 2.5

y' > 0 (upright)

s = 24

Find R

therefore:

m = -s'/s  =>  2.5 = -s'/24  =>  s' = -60

1/s + 1/s' = 2/R  =>  1/24 + -1/60 = 2/R  =>  1/40 = 2/R  =>  R = 80

The radius of the mirror is 80 cm.

(Also, I think the mirror is concave)