The figure is made up of identical cubes. If the volume of the solid is 702 cm
3,
- find the total surface area of the figure.
- how many more of such cubes is to be added to form a cube of side 21 cm?
(a)
Total number of cubes = 26
Volume of 1 cube
= 702 ÷ 26
= 27 cm
3 Length of 1 side
= ³√27
= 3 cm
Area of 1 side of cube
= 3 x 3
= 9 cm
2 Number of exposed surfaces = 92
Total surface area of the figure
= 92 x 9
= 828 cm
2 (b)
Volume of the cube with 21 cm side
= 21 x 21 x 21
= 9261 cm³
Total number of cubes
= 9261 ÷ 27
= 343
Number of more cubes needed
= 343 - 26
= 317
Answer(s): (a) 828 cm
2; (b) 317