The line through the points (h, 3) and (4, 1) intersects the line `7x-9y-19=0`at right angle. Find the value of h.

Explanation

To solve the problem, we need to find the value of \( h \) such that the line through the points \( (h, 3) \) and \( (4, 1) \) intersects the line given by the equation \( 7x - 9y - 19 = 0 \) at right angles.

### Step-by-Step Solution:

1. **Find the slope of the line through the points \( (h, 3) \) and \( (4, 1) \)**:
The formula for the slope \( m \) between two points \( (x_1, y_1) \) and \( (x_2, y_2) \) is:
\[
m = \frac{y_2 - y_1}{x_2 - x_1}
...