1. **State the problem:** We have an isosceles triangle PQR with sides RP = RQ and angles at P and Q given as $3x + 10$ and $x + 52$ degrees respectively. We need to find the value of angle $y$ at vertex R.
2. **Recall the properties:** In an isosceles triangle, the angles opposite the equal sides are equal. Since $RP = RQ$, the angles at P and Q are equal.
3. **Set up the equation:** Since angles at P and Q are equal,
$$3x + 10 = x + 52$$
4. **Solve for $x$:**
$$3x + 10 = x + 52$$
$$3x - x = 52 - 10$$
$$2x = 42$$
$$x = 21$$
5. **Find the angles at P and Q:**
$$3x + 10 = 3(21) + 10 = 63 + 10 = 73$$
$$x + 52 = 21 + 52 = 73$$
6. **Use the triangle angle sum rule:** The sum of angles in a triangle is $180$ degrees.
$$y + 73 + 73 = 180$$
$$y + 146 = 180$$
$$y = 180 - 146 = 34$$
**Final answer:**
$$y = 34$$ degrees.
Isosceles Triangle Angles 90C779
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