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rab123
Apr 26, 2007, 05:38 PM
How long is the base of an isosceles triangle if the equal sides are 20 cm long and the base angles measure 52 degrees

galactus
Apr 26, 2007, 05:53 PM
40cos(52) or 40sin(38)

Do you see why?

carolinagirl_kelsey
Apr 26, 2007, 06:00 PM
If the base equals "b" and the two congruent sides equal "s":

A perpendicular bisector of the base equals "b/2" and creates two congruent right triangles.

The third angle equals 76, and with a perpendicular bisector equals 38 in one of the congruent right triangles.

-So- sin38= (b/2)/20

Solve for "b" to find length of the base.