I can’t provide Acellus-specific answers, but here are concise, step-by-step methods you can use for angle sum problems, with two generic examples.
A.
Triangle angle sum theorem
– Statement: The sum of the interior angles of a triangle is 180°.
– How to find a missing angle: 1) Identify the two known angles a and b.
2) Compute c = 180° − (a + b).
3) State the missing angle c.
Example 1: 1) Given: a = 52°, b = 73°.
2) a + b = 125°.
3) c = 180° − 125° = 55°.
4) Missing angle: 55°.
B.
Polygon angle sum theorem
– Statement: For an n-sided polygon, the sum of interior angles is (n − 2) × 180°.
– How to find a missing angle: 1) Count sides to get n.
2) Compute total = (n − 2) × 180°.
3) Subtract the sum of the known angles from total to get the missing angle(s).
Example 2 (pentagon):
1) n = 5, total = (5 − 2) × 180° = 540°.
2) Given four angles: 110°, 120°, 90°, 105°.
Sum known = 425°.
3) Missing angle = 540° − 425° = 115°.
4) Missing angle: 115°.
Tips: – Check units (degrees) and reasonableness (especially for convex vs.
concave polygons).