This study notes covers Practice Questions within Angles in Polygons for GCSE Mathematics. Revise Angles in Polygons in Geometry & Measures for GCSE Mathematics with 12 exam-style questions and 3 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 10 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Practice Questions
Q1 Calculate the sum of interior angles in a dodecagon (12-sided polygon).
Sum = (12 − 2) × 180°
Sum = 10 × 180° = 1800°
Q2 Find the size of each interior angle in a regular nonagon (9 sides).
Exterior = 360° ÷ 9 = 40°
Interior = 180° − 40° = 140°
Q3 A regular polygon has an exterior angle of 24°. How many sides does it have?
n = 360° ÷ exterior angle
n = 360° ÷ 24° = 15 sides
Q4 A hexagon has angles of 125°, 110°, 98°, 140°, and 140°. Find the sixth angle.
Sum in hexagon = (6 − 2) × 180° = 720°
Known = 125 + 110 + 98 + 140 + 140 = 613°
Sixth angle = 720° − 613° = 107°
Practice questions for Angles in Polygons
What is the sum of the interior angles of a hexagon?
Explain how the formula (n − 2) × 180° for the sum of interior angles of a polygon is derived.