Answer:
a = 7
Explanation:
This is a special trig triangles. Special trig triangles are identified by their angle measures and their sides have a unique relationship. This is a 30 - 60 - 90 triangle which has sides 1 - √3 - 2 or multiples of this. This means all 30 - 60 - 90 triangles have side lengths with the pattern 1 - √3 - 2. Here the triangle has a - 7√√3 - 14. The value of a is 7 since 7*√3 = 7√3 and 2*7 = 14.