Let's do "b" first.....since this is an octagon. the measure of <AOB = 360/8 = 45
And m<AOX is 1/2 of that = 22.5
And that's a and b
c) Note that the measure of <OAX = 90- 22.5 = 67.5
And we can find OX by the Law of Sines
OX/sin67.5 = OA/sin90 ...... (sin 90 = 1)
OX/sin67.5 = 9
OX = 9sin67.5 = about 8.3m
d) We can find AB with the Law of Cosines
AB^2 = OA^2 + OB^2 - 2(OA)(OB)cos45
AB^2 = 9^2 + 9^2 - 2(9)(9)cos45
AB^2 = 162 - 162cos45 = 47.448701447706 take the square root of both sides
AB = about 6.9m
e) The perimeter = 8(6.9)= about 55.2 m
f) Area...we have 8 congruent triangles....the area of each is given by (1/2)(9^2)sin45 = 28.6378246380735m^2
So.... 8*28.6378246380735 = about 229m^2
Hope I haven't made any serious errors here.....!!!
