Question

5. The total surface area of a cube is 486 cm². Calculate its edge.
6. A cuboid is 10 m long, 7 m wide and 5 m high. Find its total surface area.
7. The whole surface of a rectangular block is 846 cm². Find its dimension if they are proportional to 5:4:3.
8. The dimensions of a wooden box is 14 cm x 18cm x 17 cm and thickness is 1 cm. What are its inner and outer
surface areas.​

Answer 1

Answer:

Step-by-step explanation:

1)a=9cm

2) 2(10×7+7×5+5×10)

2×155

310

total surface area of cuboid=310m^3

3)Let the dimensions be 5x,4x, and 3x

Whole surface

=2(5x×4x+5x×3x+4x×3x)cm2

=94x2cm2

Now 94x2=846cm2(given)

⇒x2=9 or x=3cm

∴ Volume of the room =5x×4x×3x

=60x3=1620square.cm