Q18 of 51 Page 2

One of the angles of a triangle is equal to the sum of the other two angles. If the ratio of the other two angles is 4:5, find the angles of the triangle.


Let one of the angle be ഊ and the other two angles are ∠B and ∠C
Given one of the angles of a triangle is equal to the sum of the other two angles
i.e., ∠A = ∠B + ∠C
Also it is given the ratio of the other two angles is 4:5
Therefore , the other two angles B and C be 4x and 5x
By the given condition, we have

Thus, the angles of the triangle are 9됐, 4됐, 5됐 i.e. 90°, 40°, 50°.
Check:
(1) 40° + 50° = 90° i.e. one of the angles of a triangle is equal to the sum of the other two angles.
(2) 40:50 = 4:5 is the ratio of the other two angles.

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