Answer:
x = 7/2
Step-by-step explanation:
The whole triangle is an equilateral triangle--all the sides are the same: 7, 7, 7 and all the angles are equal: 60°, 60°, 60°.
So the line thru the triangle makes two 30°-60°-90° triangles. The shortest side of the right triangle is half the length of the hypotenuse. Also, the line cuts the angle in half (30° and 30°) and also the side: 7/2
