# what is necessary for m to be 60?

• Jun 21st 2007, 06:42 PM
sanee66
what is necessary for m to be 60?
In the figure below, ABC is an equilateral triangle. In order to have m = 60 degrees, which condition is necessary? think it is n=60 or https://www.d2l.mvps.mde.k12.ms.us/c.../quiz5b_q5.gif

CDE is an equilateral triangle.
CDE is an isosceles triangle.
n = 60 degrees
n = 90 degrees
• Jun 21st 2007, 07:44 PM
ThePerfectHacker
The picture is not working.
As well in your other posts.
• Jun 21st 2007, 08:27 PM
Jhevon
Quote:

Originally Posted by sanee66
In the figure below, ABC is an equilateral triangle. In order to have m = 60 degrees, which condition is necessary? think it is n=60 or https://www.d2l.mvps.mde.k12.ms.us/c.../quiz5b_q5.gif

CDE is an equilateral triangle.
CDE is an isosceles triangle.
n = 60 degrees
n = 90 degrees

Here's the first problem

Note that $\angle ACB \mbox { , } \angle m \mbox { and } \angle n$ are supplementary (they add up to $180^{ \circ}$), since they are angles on a straight line.

Since $\triangle ABC$ is equilateral, $\angle ACB = 60^{ \circ}$

So we have $60 + m + n = 180$

$\Rightarrow n = 180 - 60 - m$

We want $m$ to be $60^{ \circ}$ so plug that in

$\Rightarrow n = 180 - 60 - 60 = 60$

So $n$ must be $60^{ \circ}$