Surface Areas & Volumes | Exercise 13.4 | Q6

Class 9 Maths | NCERT Exercise Solutions | Surface Area of Sphere

Question 6: Find the radius of a sphere whose surface area is 154 cm2.

NCERT Solution to Class 10 Maths

Explanatory Answer | Exrecise 13.4 Question 6

Surface area of sphere = 154 cm2
Let r be the radius of the sphere.
Surface area of sphere = 4 × π × r2
Take π = $\frac{22}{7}$
154 = 4 x $\frac{22}{7}$ x r2
r2 = 154 x $\frac{7}{22 \times 4}$
r2 = $\frac{7}{2}$ x $\frac{7}{2}$
Take square root on both sides: r = $\frac{7}{2}$
Radius of the sphere = 3.5 cm

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NCERT Solutions for Class 9 Math | Chapter 13 Video Solutions

Exercise 13.4 | Surface Area of Spheres & Hemispheres

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