Question

Find the length of tape required to cover the edges of a semicircular disc of radius 14cm. *

1 point

82 cm

85 cm

72 cm

75 cm

​

Answer 1

Required Answer:-

Length of the tape required to cover the edges of a semicircular disc means the length of the tape needed is equal to the perimeter of the semi-circle$.$

Perimeter of the semi-circle is Half the perimeter of a full circle with radius 14 cm + Diameter (2 × radius)

Formula to be used: r(π + 2) cm.

• Radius = 14 cm
• Taking π = 22/7 for approximation.

Finding the length of tape:

= r(π + 2) cm

= 14(22/7 + 2) cm

= 14(22+14 / 7) cm

= 14 × 36/7 cm

= 72 cm

Therefore:-

The length of the tape required to cover the ideas of the semicircular disc is 72 cm (C)

Answer 2

$\Large{\underline{\underline{\textsf{\maltese\: {\red{Given :-}}}}}}$

☞ Radius of circular disc = 14cm

$\Large{\underline{\underline{\textsf{\maltese\: {\red{To Find :-}}}}}}$

☞ The length of tape required to cover the edges of a semicircular disc = ?

$\Large{\underline{\underline{\textsf{\maltese\: {\red{Concept Implemented :-}}}}}}$

☞ Circumference of circle (⭕) = 2πr

☞ Semi Perimeter of circle (⭕) = πr

☞ Diameter = 2 × Radius

$\Large{\underline{\underline{\textsf{\maltese\: {\red{Solution :-}}}}}}$

» Length of tape required = Semi Perimeter of circular disc + Diameter

» Length of tape required

= πr + d

= πr + 2r

= r(π + 2)

= ${14(\dfrac{22}{7} + 2 )}$cm

= ${14(\dfrac{22 \; + \; 14}{7})}$cm

= $14 \; * \; \dfrac{36}{7}$ cm

= 2 × 36 cm

= 72cm

∴ The length of tape required to cover the edges of a semicircular disc is $\underline{\underline{\bf{72 \:cm}}}$.

∴ Option 【C】is correct. ✅