**MCQs on Class 9 Surface Areas and Volumes**

**1) The formula to find the surface area of a cuboid of length (l), breadth (b) and height (h) is:**

a. lb+bh+hl

b. 2(lb+bh+hl)

c. 2(lbh)

d. lbh/2

Answer:** b**

**2) The surface area of a cube whose edge equals to 3cm is:**

a. 62 sq.cm

b. 30 sq.cm

c. 54 sq.cm

d. 90 sq.cm

Answer:** c**

Explanation: Given, a = 3 cm

Surface area of cube = 6a^{2}

SA = 6 x 3 x 3 = 54 sq.cm

**3) The surface area of cuboid-shaped box having length=80 cm, breadth=40cm and height=20cm is:**

a. 11200 sq.cm

b. 13000 sq.cm

c. 13400 sq.cm

d. 12000 sq.cm

Answer:** a**

Explanation: surface area of the box = 2(lb + bh + hl)

S.A. = 2[(80 × 40) + (40 × 20) + (20 × 80)]

= 2[3200 + 800 + 1600]

= 2 × 5600 = 11200 sq.cm.

**4) The volume of a hemisphere whose radius is r is:**

a. 4/3 πr^{3}

b. 4πr^{3}

c. 2πr^{3}

d. ⅔ π r^{3}

Answer:** d**

**5) If the radius of a cylinder is 4cm and height is 10cm, then the total surface area of a cylinder is:**

a. 440 sq.cm

b. 352 sq.cm.

c. 400 sq.cm

d. 412 sq.cm

Answer:** b**

Explanation: Total Surface Area of a Cylinder = 2πr(r + h)

TSA = 2 x 22/7 x 4(4 + 10)

= (2x22x4x14)/7

= (2x22x4x2)

= 352 sq.cm

**6) The curved surface area of a right circular cylinder of height 14 cm is 88 cm ^{2}. The diameter of the base is:**

a. 2 cm

b. 3cm

c. 4cm

d. 6cm

Answer:** a**

Explanation: Curved surface area of cylinder = 88 sq.cm

Height = 14 cm

2πrh = 88

r = 88/2πh

r=1 cm

Diameter = 2r = 2cm

**7) The Curved surface area of a right circular cylinder is 4.4 sq.cm. The radius of the base is 0.7 cm. The height of the cylinder will be:**

a. 2 cm

b. 3 cm

c. 1 cm

d. 1.5 cm

Answer:** c**

Explanation: Curved surface area of cylinder = 2πrh

2πrh = 4.4

h = 4.4/(2πx0.7)

h = 1m

**8) The diameter of the base of a cone is 10.5 cm, and its slant height is 10 cm. The curved surface area is:**

a. 150 sq.cm

b. 165 sq.cm

c. 177 sq.cm

d. 180 sq.cm

Answer:** b**

Explanation: Diameter = 10.5, Radius = 10.5/2

Slant height, l = 10cm

Curved surface area of cone = πrl = π(5.25)(10)

CSA = 165 sq.cm

**9) If slant height of the cone is 21cm and the diameter of the base is 24 cm. The total surface area of a cone is:**

a. 1200.77 sq.cm

b. 1177 sq.cm

c. 1222.77 sq.cm

d. 1244.57 sq.cm

Answer:** d**

Explanation: Total surface area = πr(l + r)

r = 24/2 = 12 cm

l = 21 cm

TSA = π(12)(21 + 12) = 1244.57 sq.cm

**10) The surface area of a sphere of radius 14 cm is:**

a. 1386 sq.cm

b. 1400 sq.cm

c. 2464 sq.cm

d. 2000 sq.cm

Answer:** c**

Explanation: Radius of sphere, r = 14 cm

Surface area = 4πr^{2}

= 4 x 22/7 x (14)^{2} = 2464 sq.cm.