Question

PS = SR
Column A: \(x\)
Column B: \(y\)

• A. Quantity A is greater
• B. Quantity B is greater
• C. The two quantities are equal
• D. The relationship cannot be determined from the information given

Hint:

For geometry problems in quantitative comparison where the diagram is not fixed, try "dragging" a vertex to create extreme cases (e.g., a very tall, skinny triangle vs. a very short, wide one). If the relationship between the quantities changes, the answer is (D).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This question asks to compare two angles in a triangle where a median (QS) is drawn. The relationship between the angles will depend on the other properties of the triangle, which are not given. We can test different cases to see if the relationship holds.
Step 2: Detailed Explanation:
The only information given is that S is the midpoint of the side PR, meaning QS is a median. The relationship between angle \(x\) (part of the vertex angle) and angle \(y\) (a base angle) is not fixed. Let's demonstrate this by considering two different triangles.
Case 1: Let \(\triangle PQR\) be an isosceles triangle with PQ = QR.
In this case, the median QS is also an altitude and an angle bisector. So, \(\angle P = \angle R = y\). In the right-angled triangle \(\triangle QSR\), the sum of acute angles is \(90^\circ\). So, \(\angle SQR + \angle R = 90^\circ\). Also, since QS is an angle bisector, \(\angle PQS = \angle SQR = x\). Thus, \(x + y = 90^\circ\). In this scenario, we don't know if \(x \textgreater y\) or \(y \textgreater x\). For instance, if \(\triangle PQR\) is a tall and narrow isosceles triangle, y will be large (close to 90) and x will be small. If it is a short and wide isosceles triangle, y will be small and x will be large (close to 90).
Case 2: Let's use coordinates to create a skewed triangle.
Let P = (-2, 0), R = (2, 0), so S is at the origin (0, 0).
- Scenario A: Let Q = (0, 3). This is a tall isosceles triangle. QS = 3. QR = \(\sqrt{(2-0)^2 + (0-3)^2} = \sqrt{13}\). In \(\triangle QSR\), which is a right triangle, \(\tan(y) = QS/SR = 3/2\), so \(y \approx 56.3^\circ\). And \(\tan(x) = SR/QS = 2/3\), so \(x \approx 33.7^\circ\). Here, \(y \textgreater x\). - Scenario B: Let Q = (1, \(\sqrt{3}\)). PR = 4. PQ = \(\sqrt{(1 - (-2))^2 + (\sqrt{3}-0)^2} = \sqrt{9+3} = \sqrt{12}\). QR = \(\sqrt{(2-1)^2 + (0-\sqrt{3})^2} = \sqrt{1+3} = \sqrt{4} = 2\). Here, the triangle is scalene. We can use the Law of Cosines to find the angles, but it is clear from changing the shape of the triangle that the relationship between x and y is not fixed.
Step 3: Final Answer:
Since we can construct scenarios where \(y \textgreater x\) and other scenarios where \(x \textgreater y\), the relationship cannot be determined from the information given.