The figure shows a plastic cuboid that measures 122 cm by 25 cm by 25 cm.
- Find the maximum number of 7-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
= 122 ÷ 7
= 17 r 3
Breath = Height
Number of cubes along the breadth or height
= 25 ÷ 7
= 3 r 4
Maximum number of 7 cm cubes
= 17 x 3 x 3
= 153
(b)
Area of the 2 squares
= 2 x 25 x 25
= 1250 cm
2 Area of the top and bottom bases
= 2 x 122 x 25
= 6100 cm
2 Area of 1 L-shaped side
= 122 x 4 + (25 - 4) x 3
= 488 + 63
= 551 cm
2Area of 2 L-shaped sides
= 2 x 551
= 1102 cm
2 Total surface area
= 6100 + 1250 + 1102
= 8452 cm
2 Answer(s): (a) 153; (b) 8452 cm
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