pleae solve when you know do not give advice to gain point. andwer of 18 is 143 pleade solve
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Anji210:
please show fig 5.4
Give the figure mentioned in the question
for which question u need the explanation
17 or 18
18
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circumference of a circle is 2*22/7*r
circumference of a semicircle is 1/2*2*(22/7)*r=(22/7)*r
circumference of 1st circle is (22/7)*0.5
circumference of 2nd circle is (22/7)*1.0
......
circumference of 13th circle is (22/7)*6.5
so the series is,(22/7)*(0.5,1.0,.......6.5)=S
length of the spiral=sum of series
=(22/7)*S
where,
S=(n/2)(a+l)
n=13,a=0.5,l=6.5
S=(13/2)(0.5+6.5)
=(13*7)/2
=45.5
length of spiral=sum of series
=(22/7)*S
=22/7*45.5
=22*6.5
∴length of the spiral=143
circumference of a semicircle is 1/2*2*(22/7)*r=(22/7)*r
circumference of 1st circle is (22/7)*0.5
circumference of 2nd circle is (22/7)*1.0
......
circumference of 13th circle is (22/7)*6.5
so the series is,(22/7)*(0.5,1.0,.......6.5)=S
length of the spiral=sum of series
=(22/7)*S
where,
S=(n/2)(a+l)
n=13,a=0.5,l=6.5
S=(13/2)(0.5+6.5)
=(13*7)/2
=45.5
length of spiral=sum of series
=(22/7)*S
=22/7*45.5
=22*6.5
∴length of the spiral=143
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