Scale Factor and Dilation Part 2

Draw a rectangle on your graph paper with dimensions of 6cm by 4cm Draw another rectangle on your graph paper where the above dimensions have been multiplied by a scale factor of 2 8cm 12cm Length width perimeter area 6cm 4cm 20cm 24cm² 12cm 8cm 40cm 96cm²

Draw a rectangle on your graph paper with dimensions of 6cm by 4cm Draw another rectangle on your graph paper where the above dimensions have been multiplied by a scale factor of 3 12cm 18cm Length width perimeter area 6cm 4cm 20cm 24cm² 18cm 12cm 60cm 216cm²

The rectangle below will be dilated by a scale factor of 3 The rectangle below will be dilated by a scale factor of 3. What is the new rectangle’s area and perimeter? 2m 6 m 10m 30m P = 2 + 10 + 2 + 10 P = 6 + 30 + 6 + 30 P = 24 m P = 72 m A = 2 • 10 A = 6 • 30 A = 20 m² A = 180 m²

Sooo….. What really happened?? Old perimeter Scale factor 3 New perimeter P = 24 m P = 72 m 24 • 3 = 72 Multiply the old perimeter by the scale factor to get the new perimeter Old area Scale factor 3 New area A = 20 m² A = 180 m² 20 • 3 ≠ 180 20 • 9 = 180 20 • 3² = 180 Multiply the old area by the scale factor squared to get the new area

Which statement best describes the change in the perimeter of a rectangle if all of its side lengths are multiplied by 4? A The new perimeter will be 12 times as large as the perimeter of the original rectangle B The new perimeter will be 16 times as large as the perimeter of the original rectangle C The new perimeter will be 4 times as large as the perimeter of the original rectangle D The new perimeter will be 8 times as large as the perimeter of the original rectangle

Which statement best describes the change in the area of a rectangle if all of its side lengths are multiplied by 4? A The new area will be 12 times as large as the area of the original rectangle B The new area will be 16 times as large as the area of the original rectangle C The new area will be 4 times as large as the area of the original rectangle D The new area will be 8 times as large as the area of the original rectangle

Answer bank for CBA review # 2 3.02 9 11 12 18 20 60 68 112.35 113.04 310 400 1536

The rectangle below will be dilated by a scale factor of 3 The rectangle below will be dilated by a scale factor of 3. What is the new rectangle’s area and perimeter? P = P = P = P = A = A = A = A =

Sooo….. What really happened?? Old perimeter Scale factor 3 New perimeter P = P = Multiply the _____________ by the scale factor to get the new perimeter Old area Scale factor 3 New area A = A = 20 • 180 20 • 180 20 • 180 Multiply the _________by the scale factor _______ to get the new area

Which statement best describes the change in the perimeter of a rectangle if all of its side lengths are multiplied by 4? The new perimeter will be 12 times as large as the perimeter of the original rectangle The new perimeter will be 16 times as large as the perimeter of the original rectangle The new perimeter will be 4 times as large as the perimeter of the original rectangle The new perimeter will be 8 times as large as the perimeter of the original rectangle

Which statement best describes the change in the area of a rectangle if all of its side lengths are multiplied by 4? The new area will be 12 times as large as the area of the original rectangle The new area will be 16 times as large as the area of the original rectangle The new area will be 4 times as large as the area of the original rectangle The new area will be 8 times as large as the area of the original rectangle