Question

A rectangular strip, 16 cm x 3.5 cm is rotated about the longer side. Find the whole surface area of the solid thus generated

Answer 1

Total Surface Area of Cylinder = $729\ cm^2$

Step-by-step explanation:

Given, Length of rectangle = 16 cm

Breadth of rectangle = 3.5 cm

If a rectangle is rotated around its length,then a cylinder is formed

In cylinder ,radius = 3.5 cm

Height = 16cm

We know that,Total Surface Area of Cylinder = $2\pi r(r+h)$

                                                                           = $2\times 22/7 \times 3.5(3.5 + 16)$

                                                                           = $729\ cm^2$

Answer 2

Answer:

• 429 cm²

Step-by-step explanation:

Given

• Radius = 3.5 cm
• Height = 16 cm

To find

• Whole surface area or total surface area.

Solution

Total surface area of cylinder,

• 2πr (r + h)

Substituting we get,

• 2 × 22/7 × 35/10 (35/10 + 16)
• 44/7 × 35/10 (35/10 + 16)
• 22 × 19.5
• 429

Hence, the total surface area is 429 cm².