Question

Find the cost of polishing the curved surface of the right circular cylinder, whose diameter is 7cm and height is 12cm , at the rate of 50 paise per cm

Answer 1

$\bf{\underline{Question:-}}$

Find the cost of polishing the curved surface of the right circular cylinder, whose diameter is 7cm and height is 12cm , at the rate of 50 paise per cm.

$\bf{\underline{Given:-}}$

• Diameter of right circular cylinder = 7cm
• Height of right circular cylinder = 12cm
• Radius = Diameter ÷ 2 = 7/2 cm

$\bf{\underline{To\:Find:-}}$

• Cost of polishing = ?

$\bf{\underline{Formula:-}}$

• Curved surface area of cylinder = 2πrh

$\bf{\underline{Solution:-}}$

→ C.S.A = 2× 22/7 × 7/2 × 12

→ C.S.A = 44/7 × 3.5 × 12

→ C.S.A = 44/7 × 42

→ C.S.A = 264cm²

$\bf{\underline{Therefore:-}}$

• The curved surface area = 264cm²

$\bf{\underline{ Now:-}}$

Cost of polishing = 0.5 per cm

→ C.S.A × Cost of polishing

→ 264 × 50 paise ( changing paise into rupees ).

→ 264 × 50/100 ₹

→ 264 × 1/2₹

→ 132 ₹

$\bf{\underline{Hence:-}}$

• Cost of polishing = 132 ₹

Answer 2

Step-by-step explanation:

Question:−

Find the cost of polishing the curved surface of the right circular cylinder, whose diameter is 7cm and height is 12cm , at the rate of 50 paise per cm.

\bf{\underline{Given:-}}

Given:−

Diameter of right circular cylinder = 7cm

Height of right circular cylinder = 12cm

Radius = Diameter ÷ 2 = 7/2 cm

\bf{\underline{To\:Find:-}}

ToFind:−

Cost of polishing = ?

\bf{\underline{Formula:-}}

Formula:−

Curved surface area of cylinder = 2πrh

\bf{\underline{Solution:-}}

Solution:−

→ C.S.A = 2× 22/7 × 7/2 × 12

→ C.S.A = 44/7 × 3.5 × 12

→ C.S.A = 44/7 × 42

→ C.S.A = 264cm²

\bf{\underline{Therefore:-}}

Therefore:−

The curved surface area = 264cm²

\bf{\underline{ Now:-}}

Now:−

Cost of polishing = 0.5 per cm

→ C.S.A × Cost of polishing

→ 264 × 50 paise ( changing paise into rupees ).

→ 264 × 50/100 ₹

→ 264 × 1/2₹

→ 132 ₹

\bf{\underline{Hence:-}}

Hence:−

Cost of polishing = 132 ₹