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GB-28-04-001 · Regular polygons

Each interior angle of a regular polygon is 168168 degrees.

(a) Find the number of sides.

(b) 2 of these polygons are drawn separately. Find the total number of their sides.

Part (a) Exterior and Interior Angles of a Regular Polygon Booklet p. 73
Method
1) Use EA + IA = 180° to find Exterior Angle (EA)
2) Use n = 360° ÷ EA ("360 / EA / n" triangle)
Worked Example (GB-28-04-001 · Part (a))
Find the number of sides.
Booklet p. 73: IA+EA=180∘\mathbf{IA + EA = 180^\circ} and n=360∘EA\mathbf{n = \frac{360^\circ}{EA}}
1) Exterior angle = 1212 degrees.
2) 30
30
Polygon Exterior (p. 73)
360° EA n
Part (b) Exterior and Interior Angles of a Regular Polygon Booklet p. 73
Method
1) Use EA + IA = 180° to find Exterior Angle (EA)
2) Use n = 360° ÷ EA ("360 / EA / n" triangle)
Worked Example (GB-28-04-001 · Part (b))
2 of these polygons are drawn separately. Find the total number of their sides.
Booklet p. 73: IA+EA=180∘\mathbf{IA + EA = 180^\circ} and n=360∘EA\mathbf{n = \frac{360^\circ}{EA}}
1) 60
60
Polygon Exterior (p. 73)
360° EA n