One of the equal angles of an isosceles triangle is 55 degrees. If the base is 20 cm, what is the perimeter and the area?

Answer 1

So the other angle must be 180-2(55) or 70°
draw in the height, h
You now have a right-angled triangle, let the hypotenuse be x

you can find the height by
tan 55° = h/10

you can find the side by
cos 55° = 10/x

once you have x, you can find the perimeter.
once you have h, you can find the area by
area = (1/2)(20)(h)

Answer 2

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