Surface Area Learning

Introduction to lateral surface learning:
Lateral surface area in a solid is the sum of the surface areas of all its faces without the base of the solid. Or Lateral surface area means the area of the sides only -- without the top and bottom. Lateral surface area is found for an object around its outer area. Lateral surface area are usually expressed in terms of some square units.


lateral surface area learning formula:


Formula for Lateral surface area:

Cube = 4b^2, where b is the base of a cube

Sphere is 4pr^2, where r is the radius of the sphere.

Cone = p × r × l, where r and l are the radius and slant height of the cone

Cylinder = 2prh, where r is the radius and h is the height of the cylinder

Right triangular pyramid = 3 × area of lateral faces

Pentagonal prism = 5 × area of each rectangle

Please express your views of this topic Intersecting Lines by commenting on blog.

Examples for learning of lateral surface area:

Example 1:

Find the lateral surface area of a pentagonal prism, if a = 5 cm and b = 14 cm.

Solution:

Step 1: In the given figure, the base of the prism is a regular pentagon.

Step 2: All five rectangles are congruent.

Step 3: Lateral surface area of the prism = 5 × area of each rectangle

Step 4: = 5 × 5 × 14 [Substitute the values.]

Step 5: = 350

So, Lateral surface area of the pentagonal prism = 350 cm2.

Example 2:

Height and radius of the cone is 5yard and 7 yard.Find the lateral surface area of the given cone.

Solution: Lateral surface area of the cone = prl

Step 1:Slant height of the cone, l =v(25+49)      [l =vr2+h2.]

l = 8.6 yard

Step 2: Lateral surface area = 3.14 × 7 × 8.6   [As r = 7 andl = 8.6]

=

So, the lateral surface area of the cone = 189.03 sq yd.

Practice problem for lateral surface area learning;

1) Find the lateral surface area for of a sphere radius (r) = 3cm ?

Answer:  113.04