A piece of wire (ABCDEF…) is used to make a pattern formed from many concentric semi-circular arcs, AB, CD, EF… joined by short intervals BC, DE, FG… The diameter of the smallest semi-circles is 8cm and each interval is 3cm.
i) What is the length of the 20th semi-circular arc?
ii) How much wire is needed to form a pattern containing 20 semi-circular arcs?
(The diagram looks like a rainbow)
This question has really confused me and i would greatly appreciate some help, the answers are 61pi (cm) and 650pi + 57
thank you to anyone who can help