Question

find the perimeter of the following shapes to 1 DP. Take π=3.14​

Answer 1

$\sf Answer$

We are asked to find the Perimeter of the above figure (Not a big deal :P) This shape is made up of two semi circles along with a rectangle whose length and breadth 16 cm and 3 cm respectively.

All you need to know is that Circumference of a semi circle is half to that of Circe.

Circumference of Circle = 2πr

So, Circumference of a semi circle = πr

Taking π = 3.14 (Since answer would be in decimal so, don't think that by taking 22/7 we would escape from the long Calculation xD)

Also, if you see the shape clearly you would make it out easily that the length of the rectangle which is 16 cm is contributing to be the radius of both semi circle.

Circumference of Semi Circle = 3.14 × 16

Circumference = 50.24 cm

We have two semi circles so, 50.24 × 2 = 100.48 cm.

[See you can also do it like we have two semi circles with same radius then obv it's makes a complete circle... so we have to find a Circumference of a single Circle •,•]

Perimeter of Rectangle = 2(Length + Breadth)

Perimeter of Rectangle = 2(16 + 3) = 38 cm

Perimeter of this whole shape = 100.48 + 38

= 138.48 = 138.5 cm (correct upto 1 d.p.)

Answer 2

above answer is the correct