Page 343 - Math Smart - 7

O Draw:
a) three different rectangles, each with an area of 12 cm^. Try and Apply ►
Write down the lengths of the sides.
a) Calculate the area of each
b) four different rectangles, each with an area of 30 cm^.
field.
Write down the dimensions of each rectangle.
80 m
Calculate the perimeter of each rectangle. i)
72 cm
O A painting has a rectangular frame 50 mm 20 m
wide. The outer dimensions of the framed
painting are 42 cm by 72 cm.
Calculate 42 cm il) 40 m
4
a) the total area of the painting and frame.
b) the area of the part of the painting that
we can see.
c) the area of the frame.
b) Fencing is charged per
d) the perimeter of the outer edge of the frame.
metre. Which field
e) the perimeter of the inner edge of the frame.
is cheaper to fence?
Complete the following
Converting units in area sentences.
The rectangle and the
Sometimes we need to convert from one unit of measurement of area, square both have the same
to another. 1 m . However,
1 cm
the perimeter of the
1 mm
1 m rectangle is
1 cm
than the perimeter of
1 mm
the square. Therefore, it
Area = 1 mm Area = 1 cm' Area = 1 m'
is cheaper to fence the
Converting cm^ to mm 2 field.
10 mm
1 cm
When converting cm^ to
1 cm 10 mm
mm^ multiply by 100.
When converting mm^ to
1 cm X 1 cm = 1 cm^ 10 mm X 10 mm = 100 mm'
cm^ divide by 100.
So, 1 cm^ = 100 mm^
Since 100 mm^ = 1 cm^
1 mm^ = 1 -r 100
= 0.01 cm^

Converting m^ to cm^
100 cm When converting m^ to
1 m
cm^ multiply by 10 000.
When converting cm^ to
1 m 100 cm
m^ divide by 10 000.

1 m X 1 m = 1 m^ 100 cm x 100 cm = 10 000 cm^
So, 1m^= lOOOOcm^