Question

A spiral is made up of successive semicircles with the centres alternately at A and Breakfast starting at centre A of radii 0.5 cm 1 cm 1.5 cm what is total length of a spiral made up of 13 consecutive spirals ( value of pie is 22/7)​

Answer 1

Explanation:

Given

n=13

$a = 0.5\pi$

$d = 0.5\pi$

Sn=n/2[2a+(n-1)d]

$s13 = \frac{13}{2} (2 \times 0.5\pi + 12 \times 0.5 \pi) \\ \pi = \frac{22}{7} \\ s13 = 7.5 \times (1 \times \frac{22}{7} + 6×22/7) \\ s13 = 7.5 \times ×22/7 \frac{22 + 42}{7} \\ s13 = 143cm$

Therefore,

The total length of spirals made up by of thirteen semicircle is 143 cm

Answer 2

Answer:

Explanation:

it is given a = 0.5 pie

d = 0.5 pie

Sn=n/2[2a+(n-1)d]

13 S = 13/2(2 x 0.5 pie + 12 x 0.5 pie )

after calculation you get

143 cm