Question

If triangle ABC is an equilateral triangle with side 21cm, Find the perimeter of the given figure. ​

Answer 1

$\huge \fbox \red{Answer}$

Given:

• ∆ABC is a equilateral triangle.
• Side of the ∆ABC is 21cm.

To Find:

• Perimeter of ∆ABC

Solution:

Perimeter of ∆ABC = Sum of all sides.

= 21 + 21 + 21

= 63cm

Hence, the perimeter of ∆ABC is 63cm.

Answer 2

In the given picture, we get 3 semi circles, and a equilateral Δ.

here we have to find out the perimeter of 3 semi circles and a equilateral Δ.

We know that the perimeter of the circle is = 2πr

∴ perimeter of half the circle would be = $\frac{1}{2}$ × 2πr

we see that there are 3 semi circles in the given figure.

which makes it 1 circle (whole) and one semi circle

let's find the perimeter of one whole circle = 2πr

                                                                         = 2 ×$\frac{22}{7}$ × 10.5= 66cm    ( r = $\frac{21}{2}$cm)

now perimeter of half semi circle = 66/2= 33 cm

In next step we will find out the perimeter of  ABC equilateral triangle with side 21cm = 3 × sides

                          = 3 × 21 cm

                         = 63cm

Hence,  the perimeter of the given figure = perimeter of 3 semi circles and ABC equilateral Δ.

                      =66 cm+ 33 cm + 63cm= 162 cm

Ans :- the perimeter of the given figure will be 162 cm.

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