Theory question 103
Mensuration of Plane ShapesConcrete blocks of length 14/25 m were laid end to end along the four sides of a rectangular lawn 28 m long and 21 m wide.
(a) How many block were required to complete one layer?
(b) If each block costs GH¢ 1.80 and the cost of labor is one-third the cost of a block, find the total cost of laying the blocks.
Show the model answer
Model answer
(a) Perimeter = 2(28 + 21) = 98 m; blocks = 98 ÷ 14/25 = 175
(b) Blocks: 175 × 1.80 = GH¢315; labour = ⅓ × 315 = GH¢105
Total cost = GH¢420.00
Explanation
The blocks run round the perimeter.