SOLUTION: Hi, could you please find the value for a: I know that the larger triangle has the angles of 18(given), 90 (angle between radii and tangent) and 72 (90-18) but I don't know wher

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Question 1046923: Hi, could you please find the value for a:
I know that the larger triangle has the angles of 18(given), 90 (angle between radii and tangent) and 72 (90-18) but I don't know where to go from there.
Please show all working thanks.
diagram: http://imgur.com/a/Ix0Fp
(ps. is there any other way to show a diagram on this website without using an external page?)

Answer by KMST(5328) (Show Source):
You can put this solution on YOUR website!
The angle is a central angle in a circle.
It is formed by two radii, and has its vertex at , the center of the circle
The angle measuring is an inscribed angle on the same circle.
It has its vertex on the circle.
They are both acute angles intercepting the same arc.
in a case like that the measure of the inscribed angle is half of the measure of the central angle.
So, .