CBSE Class 9 Heron’s Formula MCQs – Finding Area of Triangles Using Semi-Perimeter
CBSE Class 9 Heron’s Formula MCQs – Finding Area of Triangles Using Semi-Perimeter
Class: 9 | Subject: Mathematics | Chapter: 10 – Heron’s Formula
Board: CBSE | Based on Latest NCERT Curriculum
Board: CBSE | Based on Latest NCERT Curriculum
These MCQs are strictly based on the CBSE Class 9 Mathematics syllabus and NCERT textbook. Ideal for exams and concept clarity.
1. Heron’s formula is used to find the:
Answer: B.
Heron’s formula calculates area when all three sides are known.
Heron’s formula calculates area when all three sides are known.
2. Semi-perimeter (s) of a triangle with sides a, b, c is:
Answer: B.
Semi-perimeter s = (a+b+c)/2.
Semi-perimeter s = (a+b+c)/2.
3. Area formula using Heron is:
Answer: A.
Area = √(s(s−a)(s−b)(s−c)).
Area = √(s(s−a)(s−b)(s−c)).
4. Find semi-perimeter if sides are 6 cm, 8 cm, 10 cm:
Answer: A.
s = (6+8+10)/2 = 24/2 = 12 cm.
s = (6+8+10)/2 = 24/2 = 12 cm.
5. Area of triangle with sides 3, 4, 5 is:
Answer: A.
s=6; Area=√(6×3×2×1)=√36=6 sq cm.
s=6; Area=√(6×3×2×1)=√36=6 sq cm.
6. If s=10, a=6, b=8, c=6, area equals:
Answer: A.
Area=√(10×4×2×4)=√320=~17.9 (approx concept-based).
Area=√(10×4×2×4)=√320=~17.9 (approx concept-based).
7. Heron’s formula is useful when:
Answer: B.
Used when three sides known.
Used when three sides known.
8. Semi-perimeter of triangle with sides 5,5,6:
Answer: A.
(5+5+6)/2=8.
(5+5+6)/2=8.
9. If area=√(s(s−a)(s−b)(s−c)), expression inside root must be:
Answer: C.
Area cannot be imaginary.
Area cannot be imaginary.
10. Heron’s formula applies to:
Answer: A.
Works for all triangles.
Works for all triangles.
11. If sides are equal, triangle is:
Answer: C.
All sides equal.
All sides equal.
12. Perimeter of triangle with sides 4,5,6:
Answer: A.
4+5+6=15.
4+5+6=15.
13. Semi-perimeter is half of:
Answer: C.
Definition.
Definition.
14. Area from Heron formula always positive because:
Answer: A.
Triangle inequality ensures positivity.
Triangle inequality ensures positivity.
15. If sides are 7,8,9, semi-perimeter is:
Answer: A.
(7+8+9)/2=12.
(7+8+9)/2=12.
16. If s=a=b=c, triangle is:
Answer: B.
All equal.
All equal.
17. Heron’s formula avoids use of:
Answer: B.
No need of height.
No need of height.
18. If triangle sides violate inequality, area is:
Answer: C.
No triangle possible.
No triangle possible.
19. Heron’s formula named after:
Answer: B.
Greek mathematician Heron.
Greek mathematician Heron.
20. For triangle 13,14,15 area is:
Answer: A.
s=21; Area=√(21×8×7×6)=√7056=84.
s=21; Area=√(21×8×7×6)=√7056=84.
