Math Is Fun Forum

KitKatGal

Member

Registered: 2011-02-20

Posts: 1

Trig: HELP!

I don't know how to do this problem, please explain it to me, thanks.:

The legs of an isosceles triangle are each 5. The base is 6. Find the measure of the base angles of the triangle.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Trig: HELP!

hi KitKatGal,

The isosceles triangle has no right angle, so I expect that's why you are puzzled.

Look at my diagram below.

There is a line of symmetry down the centre of the triangle and that makes it into two triangles (both the same), each of which has a right angle.

For these triangles you know the hypotenuse is 5 and the adjacent is 3 so use inverse cos to get the angle.

Bob

Last edited by Bob (2011-02-20 21:59:00)

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