An angle is 20° less than three times its supplement. Find the angle.

Question

Accepted Answer

130°. Let the angle be x, so its supplement is 180 − x. Then x = 3(180 − x) − 20 → x = 520 − 3x → 4x = 520 → x = 130°. Check: supplement = 50°, and 3(50) − 20 = 130. Trap: 50° is the supplement, not the angle; 62.5° is what the same sentence gives if you use the COMPLEMENT instead (x = 3(90 − x) − 20).

An angle is 20° less than three times its supplement. Find the angle.

Step-by-Step Solution

Key idea: Solving 'find the angle' problems

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