The perimeter of a sector of a circle of radius rcm and angle x radians is the same as the perimeter of an equilateral triangle of side rcm. Show that x=1.

Can anyone help, I've sort of worked it out but I don't think I've done the correct wayto have gotten all the marks had it been in an exam, anyone know how to do it properly?

Posted Thu 4th April, 2013 @ 12:23 by

Kate Westall
This is AS AQA by the way

Answered Thu 4th April, 2013 @ 12:27 by

Kate Westall
Perimeter of sector = perimeter of equilateral triangle (state that both sides equal)

r + r + (r*x) = r + r + r (simplify)

2r + (r+x) = 3r (minus 2r from both sides)

r*x = r (divide both sides by r)

x = r/r (r divided by itself equals 1)

x = 1

Answered Sat 6th April, 2013 @ 14:40 by

Alex
I didnt format it very well so some of the explanation has moved onto the next line, sorry!

Answered Sat 6th April, 2013 @ 14:42 by

Alex
Thank you very much! I ended up finding the angles in triangle, but didn't know where to go! Haha. Thanks again :)

Answered Mon 8th April, 2013 @ 16:20 by

Kate Westall