The figure shows a rubber cuboid that measures 118 cm by 20 cm by 20 cm.
- Find the maximum number of 8-cm cubes that can be cut from the rubber cuboid.
- Find the total surface area of the L-shaped block after cutting.
(a)
Number of cubes along the length
= 118 ÷ 8
= 14 r 6
Breath = Height
Number of cubes along the breadth or height
= 20 ÷ 8
= 2 r 4
Maximum number of 8 cm cubes
= 14 x 2 x 2
= 56
(b)
Area of the 2 squares
= 2 x 20 x 20
= 800 cm
2 Area of the top and bottom bases
= 2 x 118 x 20
= 4720 cm
2 Area of 1 L-shaped side
= 118 x 4 + (20 - 4) x 6
= 472 + 96
= 568 cm
2Area of 2 L-shaped sides
= 2 x 568
= 1136 cm
2 Total surface area
= 4720 + 800 + 1136
= 6656 cm
2 Answer(s): (a) 56; (b) 6656 cm
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