MCQMathematics

MP Board · Class 9 · Mathematics · TrianglesIn $\Delta ABC$, $\angle A = 70^\circ$ and $\angle B = 30^\circ$. Which side of the triangle is the longest?

Q: In $\Delta ABC$, $\angle A = 70^\circ$ and $\angle B = 30^\circ$. Which side of the triangle is the longest?

Correct Answer: $AB$ Calculation:\nSum of angles in a triangle = $180^\circ$ $$\angle C = 180^\circ - (70^\circ + 30^\circ) = 80^\circ$$ \nHere, the angles are $\angle A = 70^\circ$, $\angle B = 30^\circ$, and $\angle C = 80^\circ$.\nThe largest angle is $\angle C = 80^\circ$.\nSince the side opposite to the largest angle is the longest side, the side opposite to $\angle C$ is $AB$.

Step-by-Step Solution

Correct Answer: $AB$

Calculation:\nSum of angles in a triangle = $180^\circ$ $$\angle C = 180^\circ - (70^\circ + 30^\circ) = 80^\circ$$ \nHere, the angles are $\angle A = 70^\circ$, $\angle B = 30^\circ$, and $\angle C = 80^\circ$.\nThe largest angle is $\angle C = 80^\circ$.\nSince the side opposite to the largest angle is the longest side, the side opposite to $\angle C$ is $AB$.

Detailed Options Breakdown

Option : $AB$ (Correct Answer)

Correct choice. Refer to the step-by-step verified solution guidelines above for details.

Option 1: $BC$

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Triangles.

Option 2: $AC$

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Triangles.

Option 3: Cannot be determined

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Triangles.

💡 Study Guide: This question tests core syllabus concepts from Triangles. For formulas, key summaries, and mock exam reference guides, read the full Triangles Revision Notes.

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