Plane Geometry Practice Questions
WAEC (West Africa) · WAEC Mathematics · 122 free MCQs with instant results and detailed explanations.
122
Total
32
Easy
71
Medium
19
Hard
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Sample Questions from Plane Geometry
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Q1
Easy
A rectangle has a length of 10 cm and a width of 5 cm. What is its area?
A.
15 cmยฒ
B.
50 cmยฒ
C.
30 cmยฒ
D.
100 cmยฒ
Show Answer & Explanation
Correct Answer: B
The area of a rectangle is calculated by multiplying the length by the width. Therefore, 10 cm * 5 cm = 50 cmยฒ.
Q2
Easy
What is the perimeter of a square with a side length of 4 cm?
A.
12 cm
B.
16 cm
C.
8 cm
D.
10 cm
Show Answer & Explanation
Correct Answer: B
The perimeter of a square is calculated by adding all four sides, or using the formula Perimeter = 4 ร side length. Thus, 4 ร 4 cm = 16 cm.
Q3
Easy
If the base of a triangle is 10 cm and the height is 5 cm, what is the area of the triangle?
A.
25 cmยฒ
B.
50 cmยฒ
C.
15 cmยฒ
D.
20 cmยฒ
Show Answer & Explanation
Correct Answer: A
The area of a triangle is calculated using the formula: Area = 0.5 ร base ร height. Here, Area = 0.5 ร 10 cm ร 5 cm = 25 cmยฒ.
Q4
Medium
A rectangle has a length of 8 cm and a width of 3 cm. What is the area of the rectangle?
A.
24 cmยฒ
B.
20 cmยฒ
C.
30 cmยฒ
D.
18 cmยฒ
Show Answer & Explanation
Correct Answer: A
The area of a rectangle is calculated as length multiplied by width. Therefore, Area = 8 cm * 3 cm = 24 cmยฒ.
Q5
Medium
What is the measure of each interior angle in a regular pentagon?
A.
108ยฐ
B.
120ยฐ
C.
90ยฐ
D.
135ยฐ
Show Answer & Explanation
Correct Answer: A
The formula for the measure of each interior angle in a regular polygon is (n-2) * 180ยฐ / n. For a pentagon (n=5), each angle = (5-2) * 180ยฐ / 5 = 108ยฐ.
Q6
Medium
If the height of a triangle is doubled, how does it affect the area of the triangle?
A.
The area doubles
B.
The area remains the same
C.
The area triples
D.
The area quadruples
Show Answer & Explanation
Correct Answer: A
The area of a triangle is calculated as (1/2) * base * height. Doubling the height results in doubling the area, since the base remains unchanged.
Q7
Medium
If the radius of a circle is doubled, what happens to the area?
A.
It remains the same
B.
It doubles
C.
It quadruples
D.
It increases by 50%
Show Answer & Explanation
Correct Answer: C
The area of a circle is given by the formula A = ฯrยฒ. If the radius is doubled (r becomes 2r), the new area becomes A' = ฯ(2r)ยฒ = 4ฯrยฒ, which is four times the original area.
Q8
Hard
A rectangle has a length that is twice its width. If the area of the rectangle is 288 square meters, what is the perimeter of the rectangle?
A.
96 m
B.
72 m
C.
48 m
D.
144 m
Show Answer & Explanation
Correct Answer: B
Let the width be x m. Then the length is 2x m. Area = length * width = 2x * x = 288. Solving gives x = 12 m, hence perimeter = 2(2x + x) = 72 m.
Q9
Hard
A circle is inscribed in a triangle ABC. The lengths of the sides are 10 cm, 14 cm, and 16 cm. What is the radius of the inscribed circle?
A.
5 cm
B.
6 cm
C.
8 cm
D.
4 cm
Show Answer & Explanation
Correct Answer: D
The radius (r) of the inscribed circle can be calculated using the formula r = A / s, where A is the area of the triangle and s is the semi-perimeter. The semi-perimeter s = (10 + 14 + 16) / 2 = 20. The area A can be calculated using Heron's formula. After calculating, we find r = 4 cm.
Q10
Hard
A triangle has sides of lengths 7 cm, 24 cm, and 25 cm. Determine if this triangle is a right triangle.
A.
Yes, it is a right triangle.
B.
No, it is not a right triangle.
C.
It could be a right triangle depending on angles.
D.
More information is needed.
Show Answer & Explanation
Correct Answer: A
The triangle is a right triangle because it satisfies the Pythagorean theorem: 7^2 + 24^2 = 49 + 576 = 625 = 25^2.
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Plane Geometry โ WAEC (West Africa) WAEC Mathematics Practice Questions Online
This page contains 122 practice MCQs for the chapter Plane Geometry in WAEC (West Africa) WAEC Mathematics. The questions are organized by difficulty โ 32 easy, 71 medium, 19 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.