Question 2: Find the surface area of a sphere of diameter:

(i) 14 cm

(ii) 21 cm

(iii) 3.5m

## Target Centum in CBSE 10th Maths

#### Free Online CBSE Coaching

online.maxtute.com

## NCERT Solution to Class 10 Maths

#### With Videos

### Explanatory Answer | Exrecise 13.4 Question 2

#### Part (i): Diameter of the sphere, d = 14 cm

Radius of the sphere, r = \\frac{d}{2}) = \\frac{14}{2}) = 7 cm

Surface area of sphere = 4 × π × r^{2}

Take π = \\frac{22}{7})

Surface area of sphere = 4 × \\frac{22}{7}) × 7 × 7

= 4 × 22 × 7

**= 616 cm**^{2}

#### Part (ii): Diameter of the sphere, d = 21 cm

Radius of the sphere, r = \\frac{d}{2}) = \\frac{21}{2}) cm

Surface area of sphere = 4 × π × r^{2}

Take π = \\frac{22}{7})

Surface area of sphere = 4 × \\frac{22}{7}) × \\frac{21}{2}) × \\frac{21}{2})

= 22 × 3 × 21

**= 1386 cm**^{2}

#### Part (iii): Diameter of the sphere, d = 3.5 m

Radius of the sphere, r = \\frac{d}{2}) = \\frac{3.5}{2}) m

Surface area of sphere = 4 × π × r^{2}

Take π = \\frac{22}{7})

Surface area of the sphere = 4 × \\frac{22}{7}) × \\frac{3.5}{2}) × \\frac{3.5}{2})

= 22 × 0.5 × 3.5

** = 38.5 m**^{2}