A rectangle measures 20 cm by 15.If each dimension is increased by 2.5cm,by what percentage is:a)the perimeter of the rectangle increased b)the area of the rectangle is increased.Explain in detail

Answer 1

old p = 2(15+20) = 70
new p = 2(15+2.5 + 20+2.5) = 80
So, (a) 80/70 = 1.14

old a = 29*15 = 300
new a = (20+2.5)(15+2.5) = 393.75
So, (b) 393.75/300 = 1.31

now just express those factors as % increases

Answer 2

Explain further

Answer 3

Draw three rectangles with different measures having a perimeter of 20 cm: