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AC is diameter, AE is parallel to BC and ∠BAC = 50°.

AC is diameter, AE is parallel to BC and ∠BAC = 50°. Concise Mathematics Solutions ICSE Class 10.

Statement (1) : ∠EDC + 50° = 180°.

Statement (2) : ∠EDC + ∠EAC = 180°.

  1. Both statements are true.

  2. Both statements are false.

  3. Statement 1 is true, and statement 2 is false.

  4. Statement 1 is false, and statement 2 is true.

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Answer

It is given that AC is diameter and angles in a semicircle is a right angle.

⇒ ∠ABC = 90°

Since, AE is parallel to BC and AB is transversal.

⇒ ∠ABC + ∠BAE = 180° [The sum of co-interior angles formed when a transversal intersects two parallel lines is always 180°]

⇒ 90° + ∠BAE = 180°

⇒ ∠BAE = 180° - 90°

⇒ ∠BAE = 90°

⇒ ∠BAC + ∠EAC = 90°

⇒ 50° + ∠EAC = 90°

⇒ ∠EAC = 90° - 50°

⇒ ∠EAC = 40°

AEDC form a cyclic quadrilateral and sum of either pair of opposite angles of a cyclic quadrilateral is 180°.

⇒ ∠EDC + ∠EAC = 180°

⇒ ∠EDC + 40° = 180°

So, statement 1 is false but statement 2 is true.

Hence, option 4 is the correct option.

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