Question

find the curved surface area and TSA of a cone whose height is 28 cm and diameter is 42 CM help me reply soon with answer

Answer 1

h= 28cm
d= 42cm
So r= 42/2 = 21 cm
Slant height = √h square + r square
= √28 square + 21 square
= √784+ 441
= √1225
= 35

CSA = πrl
= 22/7 × 21 × 35
= 2310 cm square

TSA = πr(l+r)
= 22/7 × 21 ( 35 + 21)
= 22/7 × 21 × 56
= 3696 cm square

Answer 2

Given : A cone whose height is 28 cm and diameter is 42 cm.

To find : The curved surface area and TSA (total surface area) of the cone.

Solution :

We can simply solve this mathematical problem by using the following mathematical process. (our goal is to calculate the CSA and TSA of the given cone)

Radius of the cone = Diameter/2 = 42/2 = 21 cm

Now, we know that, in case of a cone :

(Slant height)² = (Height)² + (Radius)²

By, putting the available data, in the above mentioned mathematical formula, we get :

(Slant height)² = (28)² + (21)²

(Slant height)² = 784 + 441

(Slant height)² = 1225

Slant height = 35 cm

Now, curved surface area (CSA) of the cone = π × radius × slant height

By, putting the available data in the above mentioned mathematical formula, we get :

Curved surface area (CSA) of the cone = π × 21 × 35 = (22/7) × 21 × 35 = 2310 cm²

And, we also know that :

Base area of a cone = π × (radius)² = (22/7) × (21)² = 1386 cm²

Total surface area (TSA) of the cone :

= Curved surface area + Base area

= 2310 + 1386

= 3696 cm²

Hence, the curved surface area (CSA) of the cone is 2310 cm² and the total surface area (TSA) of the cone is 3696 cm².