Heron's Formula Practice Questions

Class 9 · Mathematics · 1473 free MCQs with instant results and detailed explanations.

1473
Total
512
Easy
723
Medium
238
Hard

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Topics in Heron's Formula

Applications 670
Area of Triangle Using Heron's Formula 803

Sample Questions from Heron's Formula

Here are 10 sample questions. Start a quiz to get randomized questions with scoring.

Q1
Easy
Using Heron's formula, what is the area of a triangle with sides 8 cm, 15 cm, and 17 cm?
A. 60 cmยฒ
B. 68 cmยฒ
C. 72 cmยฒ
D. 77 cmยฒ
Show Answer & Explanation
Correct Answer: A
The semi-perimeter is 20 cm and the area is calculated using Heron's formula as โˆš(20(20-8)(20-15)(20-17)) = 60 cmยฒ.
Q2
Easy
If one side of a triangle is 10 cm and the other two sides are equal, what is the maximum length of the equal sides if the area must be 24 cmยฒ?
A. 12 cm
B. 10 cm
C. 8 cm
D. 6 cm
Show Answer & Explanation
Correct Answer: C
To find the equal sides, we use Heron's formula and iterate possible values, where maximum length is found to be 8 cm.
Q3
Easy
Which of the following triangles can use Heron's formula?
A. Scalene triangle
B. Isosceles triangle
C. Equilateral triangle
D. All of the above
Show Answer & Explanation
Correct Answer: D
Heron's formula is applicable to any triangle, whether scalene, isosceles, or equilateral.
Q4
Medium
A triangle has sides of lengths 5 cm, 12 cm, and 13 cm. What is the area of this triangle?
A. 30 cmยฒ
B. 35 cmยฒ
C. 36 cmยฒ
D. 31 cmยฒ
Show Answer & Explanation
Correct Answer: A
The triangle is a right triangle. Area = (1/2) * base * height = (1/2) * 5 * 12 = 30 cmยฒ.
Q5
Medium
Find the area of a triangle with sides 9 m, 12 m, and 15 m.
A. 54 mยฒ
B. 60 mยฒ
C. 72 mยฒ
D. 66 mยฒ
Show Answer & Explanation
Correct Answer: A
Using Heronโ€™s formula: s = (9+12+15)/2 = 18. Area = โˆš[18(18-9)(18-12)(18-15)] = 54 mยฒ.
Q6
Medium
If a triangle has an area of 84 mยฒ and a base of 14 m, what is the corresponding height?
A. 12 m
B. 10 m
C. 14 m
D. 8 m
Show Answer & Explanation
Correct Answer: A
Using Area = (1/2) * base * height, height = (2 * 84) / 14 = 12 m.
Q7
Medium
A triangle has a base of 8 cm and a height of 6 cm. What is its area?
A. 24 cmยฒ
B. 30 cmยฒ
C. 18 cmยฒ
D. 20 cmยฒ
Show Answer & Explanation
Correct Answer: A
Area = (1/2) * base * height = (1/2) * 8 * 6 = 24 cmยฒ.
Q8
Hard
A triangle has sides of lengths 13 cm, 14 cm, and 15 cm. What is its area using Heron's formula?
A. 84 cmยฒ
B. 90 cmยฒ
C. 96 cmยฒ
D. 72 cmยฒ
Show Answer & Explanation
Correct Answer: A
Using Heron's formula: s = (13 + 14 + 15) / 2 = 21. Area = โˆš[s(s-a)(s-b)(s-c)] = โˆš[21(21-13)(21-14)(21-15)] = 84 cmยฒ.
Q9
Hard
A triangle has an area of 60 cmยฒ and two sides measuring 8 cm and 10 cm. What could be the length of the third side?
A. 5 cm
B. 7 cm
C. 12 cm
D. 15 cm
Show Answer & Explanation
Correct Answer: B
Using Heron's formula for area, we find the possible third side must satisfy the area condition. The lengths must adhere to triangle inequality.
Q10
Hard
A triangle has two sides measuring 6 cm and 8 cm, and the area is 24 cmยฒ. What could be the length of the third side?
A. 10 cm
B. 12 cm
C. 14 cm
D. 16 cm
Show Answer & Explanation
Correct Answer: B
Use Heron's formula to check which value satisfies the area condition given the two other sides.

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Heron's Formula โ€” Class 9 Mathematics Practice Questions Online

This page contains 1473 practice MCQs for the chapter Heron's Formula in Class 9 Mathematics. The questions are organized by difficulty โ€” 512 easy, 723 medium, 238 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. This chapter covers 2 topics, giving you comprehensive coverage of the entire chapter.