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# Find the surface area of a sphere of radius:

i) 10.5 cm ii) 5.6 cm iii) 14 cm

**Solution:**

i) Radius, r = 10.5cm

Surface area of the sphere = 4πr^{2}

= 4 × 22/7 × (10.5cm)^{2}

= 1386 cm^{2}

ii) Radius, r = 5.6cm

Surface area of the sphere = 4πr^{2}

= 4 × 22/7 × (5.6cm)^{2}

= 394.24 cm^{2}

iii) Radius, r = 14cm

Surface area of the sphere = 4πr^{2}

= 4 × 22/7 × (14cm)^{2}

= 2464 cm^{2}

Thus, the surface areas of the sphere of radii 10.5 cm, 5.6 cm, and 14 cm are 1386 cm^{2}, 394.24 cm^{2}, and 2464 cm^{2} respectively.

**☛ Check: **NCERT Solutions for Class 9 Maths Chapter 13

**Video Solution:**

## Find the surface area of a sphere of radius: i) 10.5 cm ii) 5.6 cm iii) 14 cm

Class 9 Maths NCERT Solutions Chapter 13 Exercise 13.4 Question 1

**Summary:**

The surface areas of the sphere of radii 10.5 cm, 5.6 cm, and 14 cm are 1386 cm^{2}, 394.24 cm^{2}, and 2464 cm^{2} respectively.

**☛ Related Questions:**

- Find the surface area of a sphere of diameter: i) 14 cm ii) 21 cm iii) 3.5 m
- Find the total surface area of a hemisphere of radius 10 cm. (Use π = 3.14)
- The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.
- A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin-plating it on the inside at the rate of ₹16 per 100 cm².

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