Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 9

If the sides of a triangle are 3 cm, 4 cm and 5 cm, then the area is - Mathematics

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MCQ

If the sides of a triangle are 3 cm, 4 cm and 5 cm, then the area is 

Options

  • 3 cm2

  • 6 cm2

  • 9 cm2

  • 12 cm2

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Solution

6 cm2

Explanation;

Hint:

a = 3 cm, b = 4 cm, c = 5 cm

s = `("a" + "b" + "c")/2`

= `(3 + 4 + 5)/2`

= 6 cm

Area of the triangle = `sqrt("s"("s" - "a")("s" - "b")("s" - "c"))`

= `sqrt(6 xx 3 xx 2 xx 1)`

= `sqrt(36)`

= 6 cm2 

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Chapter 7: Mensuration - Exercise 7.4 [Page 263]

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Tamil Nadu Board Samacheer Kalvi Class 9th Mathematics Answers Guide
Chapter 7 Mensuration
Exercise 7.4 | Q 2 | Page 263

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