10 questions · Form 1 Mathematics Bab 9: Basic Polygons
Which triangle has 3 lines of symmetry and all interior angles equal to 60°?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. 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.
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. How many diagonals can be drawn in a pentagon?
Answer: A
For a pentagon, n = 5. Diagonals = 55 - 32 = 522 = 5.
4. 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.
5. 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.
6. Which polygon has 7 sides?
Answer: B
A 7-sided polygon is called a heptagon.
7. How many sides does an octagon have?
Answer: B
An octagon is an 8-sided polygon.
8. In an isosceles triangle ABC where AB = AC, if the vertex angle A is 40°, calculate the measure of base angle B.
Answer: A
Base angles are equal. Sum = 180°. Angle B = 180° - 40°2 = 140° / 2 = 70°.
9. What is the sum of interior angles of any quadrilateral?
Answer: C
Every quadrilateral can be divided into two triangles, making the sum of its interior angles 2 × 180° = 360°.
10. In a parallelogram ABCD, angle A = 110°. Find the measure of angle B (adjacent to A on a parallel side).
Answer: B
Interior angles between parallel lines sum to 180°. Angle B = 180° - 110° = 70°.