Question

the curved surface area of cone is 308 sol.cm and radius 7 cm find the total surface ​

Answer 1

Answer:

AL≈154.06cm²

r Radius 7cm

A Surface area 308cm²

Step-by-step explanation:

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Answer 2

Given :–

• Surface area of a cone = 308cm²
• Radius = 7cm

To Find :–

• Total surface area.

Solution :–

First, we need to find the value of height.

According to the question,

Curved Surface area of a cone = 308cm²

⟹ πrl = 308

• r = 7cm

⟹ $\dfrac{22}{\cancel{7}} \times \cancel{7}$ × 1 × h = 308

Cancel the denominator (7) and the numerator (7), we obtain

⟹ 22 × h = 308

Now, turn the L.H.S. number (22) to the R.H.S. number (308), here in the L.H.S. the number 22 is multiply by height so, after turn the number it will be divide by 308.

⟹ h = $\dfrac{\cancel{308}}{\cancel{22}}$

Cut the denominator (22) and the numerator (308) by 2, we obtain

⟹ h = $\dfrac{\cancel{154}}{\cancel{11}}$

Now, cut the denominator (11) and the numerator (154) by 11, we obtain

⟹ h = 14

Hence,

Height of a cone is 14cm.

Now, we need to find the total surface area of a cone,

Total surface area of a cone = πr(r + l)

• height = l = 14cm
• r = 7cm

⟹ $\dfrac{22}{\cancel{7}} \times \cancel{7}$ (7 + 14)

Cancel the denominator (7) and the numerator (7), we obtain

⟹ 22 × 1 × (7 + 14)

⟹ 22 × 1 × 21

⟹ 22 × 21

⟹ 462

Hence,

The total surface area of a cone is 462cm².