Answer:
3) 2.7
Step-by-step explanation:
The distance between two points
and
can be determined by:

Since the points are X(1, 2) and Y(6, 7). The distance between the two points is

the x value for the point located 1/3 the distance from X to Y,

The x value = 
X≈1.5874
(Use the answer in the photo)
4th quadrant is positive x (cos) and negative y (sin)
Use the Pythagorean Theorem to calculate the value of y (sin).
x² + y² = c²
5² + y² = 13²
25 + y² = 169
y² = 144
y = 12
Since the y-value is negative in the 4th quadrant, then y = -12