NCERT Mathematics Class 9 Exemplar Ch 12 Heron's Formula Part 3

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Exercise 12.2

Q.1. The area of a triangle with base 4 cm and height 6 cm is 24 cm2.

Answer: False, area of the triangle is

Q.2. The area of ∆ ABC is in which and

Answer: True, area of the triangle =

Q.3. The area of the isosceles triangle is , if the perimeter is and the base is

Answer: True, Each of equal side

Q.4. The area of the equilateral triangle is who’s each side is

Answer: False, area of the triangle

Q.5. If the side of a rhombus is 10 cm and one diagonal is , the area of the rhombus is

Answer: True, the other diagonal will be

Q.6. The base and the corresponding altitude of a parallelogram are and , respectively. The area of the parallelogram is

Answer: False, the area of the parallelogram is

Q.7. The area of a regular hexagon of side ‘a ‘is the sum of the areas of the five equilateral triangles with side a.

Answer: False, area is the sum of all the six equilateral triangles.

Q.8. The cost of levelling the ground in the form of a triangle having the sides , and at the rate of Rs 3 per m2 is Rs 918.

Answer: True, area

Q.9. In a triangle, the sides are given as, and The length of the altitude is corresponding to the side having length

Answer: True, area of the triangle =