Question

29. A jokers cap is in the form of right circular cone of base radius 7 cm and slant
height 25 cm. Find the area of sheet required for 10 such caps.
​

Answer 1

✬ Sheet Required = 5500 cm² ✬

Step-by-step explanation:

Given:

• A Joker's cap is in the form of right circular cone.
• Measure of base radius of cone is 7 cm.
• Measure of slant height (L) of cone is 25 cm.

To Find:

• What is the area of sheet required for 10 caps ?

Solution: First , we need to find the area of 1 such cap that is in form of circular cone.

As we know that

★ Curved Surface area of cone = πrl ★

Here,

• r = 7 cm , l = 25 cm

$\implies{\rm }$ πrl

$\implies{\rm }$ ( 22/7 $\times$ 7 $\times$ 25 ) cm²

$\implies{\rm }$ ( 22 $\times$ 25 ) cm²

$\implies{\rm }$ 550 cm²

So, The sheet required for one cap is 550 cm².

∴ Sheet required for making 10 caps

➯ 10 $\times$ 550

➯ 5500 cm².

Hence, sheet required for making 10 such caps will be 5500 cm².

Answer 2

GIVEN:

• Radius (r) of the cap = 7 cm
• Slant height (l) of the cap = 25 cm

TO FIND:

• What is the area of sheet required for 10 such caps ?

SOLUTION:

Firstly, We have to find the area of 1 cap

To find the Curved surface area of the cap, we use the formula:-

$\Large\bf{\star \: C.S.A. = \pi rl \: \star}$

According to question:-

On putting the given values in the formula, we get

Take π = 22/7

$\rm{\dashrightarrow C.S.A. = \dfrac{22}{\cancel{7}} \times \cancel{7} \times 25 }$

$\rm{\dashrightarrow C.S.A. = 22 \times 25 }$

$\bf{\dashrightarrow C.S.A. = 550 \: cm^2}$

❛ The C.S.A. of 1 cap is 550 cm² ❜

✎ Now, we have to find the C.S.A. of 10 caps

C.S.A. of 1 cap $\times$ 10 = C.S.A. of 10 caps

➧ $\rm{ 550 \times 10 = 5500 \: cm^2}$

➧ $\bf{\star \: C.S.A. \: of \: 10 \: caps = 5500 \: cm^2 \: \star}$

❝ Hence, the C.S.A. of 10 caps is 5500 cm² ❞

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