The figure shows a plastic cuboid that measures 121 cm by 25 cm by 25 cm.
- Find the maximum number of 4-cm cubes that can be cut from the plastic cuboid.
- Find the total surface area of the L-shaped block after cutting.
(a)
Number of cubes along the length
= 121 ÷ 4
= 30 r 1
Breath = Height
Number of cubes along the breadth or height
= 25 ÷ 4
= 6 r 1
Maximum number of 4 cm cubes
= 30 x 6 x 6
= 1080
(b)
Area of the 2 squares
= 2 x 25 x 25
= 1250 cm
2 Area of the top and bottom bases
= 2 x 121 x 25
= 6050 cm
2 Area of 1 L-shaped side
= 121 x 1 + (25 - 1) x 1
= 121 + 24
= 145 cm
2Area of 2 L-shaped sides
= 2 x 145
= 290 cm
2 Total surface area
= 6050 + 1250 + 290
= 7590 cm
2 Answer(s): (a) 1080; (b) 7590 cm
2