Answer:
116 degrees
Explanation:
The sum of all three angles of a triangle is 180 degrees. Here we know two of these angles immediately: 65 and 51 degrees. The third is 180 - (65 + 51), degrees, or 64 degrees.
Angle PST and this 64 degree angle form straight angles; their sum is 180 degrees. We are to find Angle PST. Do that by subtracting 64 from 180:
Angle PST = 180 - 64 degrees, or 116 degrees.