Page 345 - Math Smart - 7

Check My
Understanding

Express
a) 19 cm^ in mm^ b) 270 cm^ in mm^ c) 8600 cm^ in mm^
d) 46 m^ in cm^ e) 150 m^ in cm^, f) 2300 m^ in cm^
g) 8460 mm^ in cm^ h) 500 mm^ in cm^ i) 64 mm^ in cm^
j) 100 000 cm^ in m^ k) 350 000 cm^ in m^ 1) 7400 cm^ in m^
m) 910 mm^ in m^ n) 4881 mm^ in m^and o) 2 160 000 mm^ in m^,

© The cellphone screen measures 75 mm by 150 mm.
150 mm
a) Find the area in mm^.
b) Find the area in cm^. 75 mm
c) Find the perimeter in mm.
d) Find the perimeter in cm.

e A square has a length 13 m. Find its area in cm^.

O A rectangle has a length 18 cm and width 7 cm. Find its area in m^.
© The front cover of a picture book is a square with a length 25 cm. Find the area of the front cover.

O A rectangular field has an area of 7000 m^. It has a length of 100 m. Find Its width in cm.

Areas and perimeters of

composite figures

A composite figure or a compound shape is a shape that is made up of two or Think and Share
more basic shapes. We can break down the figure into smaller basic shapes to 9
find its total area or perimeter. This
This ccompound shape can
be divided into rectangles in
In Stage 7, you will calculate the area and perimeter of compound shapes made
different ways.
up of rectangles.

O Look at the composite figure given, 15 cm
a) Calculate its perimeter.
b) Calculate its area.
8 cm
12 cm
Think of at least one other
12 cm
way to divide the compound
shape into rectangles.

3 cm