A viewfinder has a triangular lens. Some of the measurements of the lens are shown below. Which of the following best represents the length of a?
B
26°
a
С
389
10
A
Triangle not drawn to scale

Explanation:

It's a bit strange why your teacher has the "26 degree" label pointing at a side length, rather than an actual angle. I'm assuming your teacher meant to aim it at angle C. In other words, I'm assuming they meant to say angle C = 26 degrees.

If that assumption is correct, then,

A+B+C = 180

38+B+26 = 180

B+64 = 180

B = 180-64

B = 116

Then we can use the law of sines like so:

a/sin(A) = b/sin(B)

a/sin(38) = 10/sin(116)

a = sin(38)*10/sin(116)

a = 6.84986152123146

a = 6.8

Side 'a' is approximately 6.8 inches long. So that's why the answer is choice A.

this is answer of 144 cubic meters