The three sides of a triangle are in different colors – blue, green and red. The ratio of the length of the blue side to the length of the green side to the length of the red side is 3 : 4 : 5. The perimeter of the triangle is 240 cm. a) Fill in the blank: ___ units = 240 cm b) Fill in the blank: 1 unit = ___ cm c) What is the length of the red side of the triangle?

The perimeter is the distance around the triangle. Given the ratio, the perimeter using the ratio is;

= 3 + 4 + 5

= 12 units

a. 12 units = 240 cm

The perimeter in centimetres is 240cm and in ratio is 12 units so they are equivalent.

b. 1 unit = 20 cm

If 12 units are to 240 cm, 1 unit is;

= 240/12

= 20 cm

c. Length of red side;

Red side has length of 5 units. 1 unit is 20 cm.

Length in cm is;

= 5 * 20

= 100 cm

ab will be equal to