Question

Trigonometry, please help. Medal will be given.





Find the altitude of an isosceles triangle with a vertex angle (that is, the non-base angle) of 70° and a base of 246. Draw a diagram and find the length of the altitude.

175.7
89.5
86.1

Answer 1

so first, we know isosceles triangles have 2 congruent angles, since the sum of interior angles of a triangle add to 180, what are the missing angles?

Answer 2

I'm guessing since they're congruent they'd both be 90?

Answer 3

Not quite

3 angles in the triangle

those 3 have to add to 180

So lets name them as 'x' for now

That means \[\large x + x + 70 = 180\]

so x = ?

Answer 4

x would equal 55

Answer 5

Right, so what we have is an isosceles triangle that looks like

Answer 6

Adding the base and drawing the altitude we want,