10 questions · Form 1 Mathematics Bab 9: Basic Polygons
10 questions · plays in fullscreen
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. An exterior angle of a triangle is 115°, and one of its opposite interior angles is 45°. Find the other opposite interior angle.
Answer: B
An exterior angle equals the sum of two opposite interior angles: 115° = 45° + interior angle => interior angle = 115° - 45° = 70°.
2. Which of the following quadrilaterals has diagonals that bisect each other at right angles (90°), but does NOT have all equal angles?
Answer: B
A rhombus has 4 equal sides and diagonals that intersect at 90°, but its angles are not all 90° like a square.
3. Which quadrilateral has ONLY ONE pair of parallel sides?
Answer: C
By definition, a trapezium is a quadrilateral with only one pair of parallel sides.
4. How many sides does an octagon have?
Answer: B
An octagon is an 8-sided polygon.
5. Which polygon has 7 sides?
Answer: B
A 7-sided polygon is called a heptagon.
6. How many diagonals can be drawn in a pentagon?
Answer: A
For a pentagon, n = 5. Diagonals = 55 - 32 = 522 = 5.
7. Find the exterior angle of a triangle if its adjacent interior angle is 72°.
Answer: A
An interior angle and its adjacent exterior angle lie on a straight line and sum to 180°. Exterior angle = 180° - 72° = 108°.
8. Three interior angles of a quadrilateral are 85°, 110°, and 95°. Calculate the fourth angle.
Answer: B
Sum of quadrilateral angles = 360°. Fourth angle = 360° - (85° + 110° + 95°) = 360° - 290° = 70°.
9. Which triangle has 3 lines of symmetry and all interior angles equal to 60°?
Answer: C
An equilateral triangle has 3 equal sides, 3 equal angles of 60°, and 3 lines of symmetry.
10. A quadrilateral has two pairs of equal adjacent sides and diagonals that cut at 90°. What shape is it?
Answer: C
A kite has adjacent sides equal and perpendicular diagonals.