In this page curved surface area solution6 we are going to see solution of some practice questions.

**Question 11**

If the vertical angle and the radius of the right circular cone are 60
degree and 15 cm respectively,then find its height and slant height.

**Solution:**

Vertical angle of the right circular cone = 60 degree

radius of the cone (r) = 15 cm

In the triangle ABC ∠ABC = 30°

BC = 15 cm

Opposite side (BC) = 15 cm

Adjacent side (AB) = ?

Hypotenuse side (AC) = ?

from here we need to find the measurement of the side AC. So we have to use Sinθ.

Sin θ = Opposite side/Hypotenuse side

Sin 30° = BC/AC

(1/2) = 15/AC

AC = 30 cm

**Slant height (L) = ****30 cm **

**Question 12**

If the circumference of the base of the solid right circular cone is 236 and its slant height is 12 cm, find its curved surface area.

**Solution:**

Circumference of the base = 236 cm

Slant height (L) = 12 cm

2 Π r = 236

Π r = 236/2

Π r = 118

Curved surface area of cone = Π r l

= 118 (12)

= 1416 cm

**Curved surface area of cone = 1416**** cm **

**Question 13**

A heap of paddy is in the form of a cone whose diameter is 4.2 m and height is 2.8 m. If the heap is to be covered exactly by a canvas to protect it from rain,then find the area of the canvas needed.

**Solution:**

Diameter of heap of paddy = 4.2 m

r = 4.2/2

= 2.1 m

height of paddy (h) = 2.8 m

L² = r² + h²

L = √(2.1)² + (2.8)²

L = √4.41 + 7.84

L = √12.25

L = √ 3.5 **x** 3.5

L = 3.5 cm

Curved surface area of heap of paddy = Π r l

= (22/7) **x** (2.1) **x** (3.5)

= 22 **x** (2.1) **x** (0.5)

= 23.1 cm²

**Curved surface area of paddy =**** 23.1 cm²**** **

curved surface area solution6 curved surface area solution6

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- Area
- Curved Surface Area
- Total Surface Area
- Volume
- Cylinder
- Conoid (Cone)
- Sphere
- Problems on Curved Surface Area
- Problems on Total Surface Area
- Problems on Volume
- Formulas For Shapes
- Perimeter of Sector
- Perimeter of Sector Worksheets
- Length of Arc
- Practice questions on length of arc
- Perimeter of square
- Perimeter of Parallelogram
- Perimeter of Rectangle
- Perimeter of a Triangle
- Area of a Circle
- Area of Semicircle
- Area of Quadrant
- Area of a Sector
- Area of a Triangle
- Area of Equilateral Triangle
- Area of Scalene Triangle
- Area of Square
- Area of Rectangle
- Area of Parallelogram
- Area of Rhombus
- Area of Trapezium
- Area of Quadrilateral
- Area Around Circle
- Path Ways
- Combined Figures