The figure shows a metallic cuboid that measures 141 cm by 25 cm by 25 cm.
- Find the maximum number of 7-cm cubes that can be cut from the metallic cuboid.
- Find the total surface area of the L-shaped block after cutting.
(a)
Number of cubes along the length
= 141 ÷ 7
= 20 r 1
Breath = Height
Number of cubes along the breadth or height
= 25 ÷ 7
= 3 r 4
Maximum number of 7 cm cubes
= 20 x 3 x 3
= 180
(b)
Area of the 2 squares
= 2 x 25 x 25
= 1250 cm
2 Area of the top and bottom bases
= 2 x 141 x 25
= 7050 cm
2 Area of 1 L-shaped side
= 141 x 4 + (25 - 4) x 1
= 564 + 21
= 585 cm
2Area of 2 L-shaped sides
= 2 x 585
= 1170 cm
2 Total surface area
= 7050 + 1250 + 1170
= 9470 cm
2 Answer(s): (a) 180; (b) 9470 cm
2