- A55°
- B35°
- C145°
- D125°
Step-by-Step Solution
Wall ⟂ shelf, so the triangle has angles 90°, 35° and the angle at the wall. The exterior angle at the brace–shelf corner is 180° − 35° = 145° = 90° + (angle at wall), giving 55°.
Answer: A) 55°
A wall shelf rests on a slanting brace, forming a right triangle with the wall. The brace meets the shelf at 35°. What angle does the brace make with the wall?
Class 9Exterior Angle of a TriangleGeometry — Lines and Angles
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