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Which of the following statements is tru...

Which of the following statements is true ?

A

If in a triangle, two angles are equal to `60^(@)`, then the triangle is equilateral.

B

If the angles of a triangle are in the ratio 1:1:2, then it is a right angled isosceles triangle.

C

If the angles of a triangle are in the ratio 1:2:3, then it is a right angled triangle.

D

All of these

Text Solution

AI Generated Solution

The correct Answer is:
To determine which of the statements regarding triangles is true, we will analyze each statement step by step. ### Step 1: Analyze Statement 1 **Statement 1:** If in a triangle, two angles are equal to 60 degrees, then the triangle is equilateral. 1. Let's denote the angles of the triangle as A, B, and C. 2. Given: A = 60°, B = 60°. 3. We can find angle C using the angle sum property of triangles, which states that the sum of the angles in a triangle is 180°. \[ A + B + C = 180° \] Substituting the known values: \[ 60° + 60° + C = 180° \] Simplifying: \[ 120° + C = 180° \] \[ C = 180° - 120° = 60° \] 4. Since all angles A, B, and C are equal to 60°, the triangle is equilateral. **Conclusion for Statement 1:** True. ### Step 2: Analyze Statement 2 **Statement 2:** If the angles of a triangle are in the ratio of 1:1:2, then it is a right angle isosceles triangle. 1. Let the angles be X, X, and 2X. 2. Using the angle sum property: \[ X + X + 2X = 180° \] Simplifying: \[ 4X = 180° \] \[ X = \frac{180°}{4} = 45° \] 3. Therefore, the angles are: - Angle 1 = 45° - Angle 2 = 45° - Angle 3 = 2 * 45° = 90° 4. Since two angles are equal (45°) and one angle is 90°, the triangle is indeed an isosceles right triangle. **Conclusion for Statement 2:** True. ### Step 3: Analyze Statement 3 **Statement 3:** If the angles of a triangle are in the ratio of 1:2:3, then it is a right angle triangle. 1. Let the angles be X, 2X, and 3X. 2. Using the angle sum property: \[ X + 2X + 3X = 180° \] Simplifying: \[ 6X = 180° \] \[ X = \frac{180°}{6} = 30° \] 3. Therefore, the angles are: - Angle 1 = 30° - Angle 2 = 2 * 30° = 60° - Angle 3 = 3 * 30° = 90° 4. Since one angle is 90°, the triangle is a right angle triangle. **Conclusion for Statement 3:** True. ### Step 4: Conclusion All three statements are true. Therefore, the answer is that all statements are correct. ### Final Answer **All statements are true.** ---
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