Calculate the length of an arc
which subtends an angle of 100 degrees
at the centre of a circumcised radius 14cm

Easy peasy
remember that the arc is a part of the perimiter of the circle aka circumference
also 360 degrees=circle

we are given the radius
calculate circumference
c=2pi times r
r=14
c=pi times 2 itimes 14
c=28pi

100 degrees is the arc

find what fraction of the circumferece thei srepresents
whole=360
100/360=10/36=5/18
so if circumference=28pi then multiply 5/18 by that
5/18 times 28pi=140pi/18=70pi/9
legnth=(70pi)/9 cm
if you were to aprox pi to 3.14 then the answer would be
24.4222222 cm

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.