Question
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
Answers
oobleck
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
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
Anonymous
Explain further
Anup
Draw three rectangles with different measures having a perimeter of 20 cm: