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Showing 1 question in Mathematics for Class 9. Tap a card to reveal the answer.
MathematicsSurface Areas and VolumesmediumFind the volume of a sphere of radius 7 cm. (Take pi = 22/7.)
Reveal answer ↓
What it is
A sphere's volume grows with the cube of its radius: V = (4/3) pi r^3.
Answer
Volume of a sphere = (4/3) x pi x r^3 = (4/3) x (22/7) x 7^3 = (4/3) x (22/7) x 343 = (4 x 22 x 49)/3 = 4312/3, which is about 1437.3 cubic cm.
V(sphere) = (4/3) pi r^3
- •V = (4/3) pi r^3
- •= (4/3)(22/7)(343)
- •= 4312/3 = about 1437.3 cm^3
Why learn this
It measures balls, planets, bubbles and tanks - anywhere something is round.
💡 Memory trick
Four-thirds pi r-cubed: V = (4/3) pi r^3 - the roundest formula in maths.