9514 1404 393
Answer:
3
Step-by-step explanation:
Vertical angles share a vertex point, and have opposite rays for sides. In short, they are across the point of intersection from each other. Vertical angles do not have a common side (they are <em>not</em> adjacent).
The first part of the problem is to identify angle NCA. That is shown in red in the attachment. The vertical angle is across the point of intersection. It is angle 3.
The measure of the fourth angel is 87°
The angles in an equilateral triangle are 60 degrees.
sin 60 = 9 / h where h is hypotenuse ( = side of the triangle)
h = 9 / sin 60 = 10.392
Perimeter = 3 * h = 31.18 to nearest hundredth
Do you have a photo of the picture?