A 4” x 6” photo is to be enlarged by a scale factor of 3. What will the perimeter of the new photo be?

Answer 1

Area = 4x6 = 24 square inches

3(Area) = 72 square inches with sides 2s by 3s = 6s^2 = 72, s^2 = 12, s=2sqr3

new dimensions are 4sqr3 by 6sqr3 inches or about 6.9 by 10.4

perimeter = 2(4sqr3 + 6sqr3) = 2(10sqr3) = 20sqr3 = about 34.64 inches