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तमिलनाडु बोर्ड ऑफ सेकेंडरी एज्युकेशनएसएसएलसी (अंग्रेजी माध्यम) कक्षा ९

Using Heron’s formula, find the area of a triangle whose sides are 1.8 m, 8 m, 8.2 m

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प्रश्न

Using Heron’s formula, find the area of a triangle whose sides are 1.8 m, 8 m, 8.2 m

योग
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उत्तर

Here a = 1.8 m, b = 8 m, c = 8.2 m

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

= `((1.8 + 8 + 8.2)"m")/2`

= `18/2`

= 9 m

s – a = 9 – 1.8 = 7.2 m

s – b = 9 – 8 = 1 m

s – c = 9 – 8.2 m = 0.8 

Area of triangle

= `sqrt("s"("s" - "a")("s" - "b")("s" - "c"))`

= `sqrt(9 xx 7.2 xx 1 xx 0.8)`

= `sqrt(9 xx 5.76)`

= `sqrt9 xx sqrt(576/100)`

= `3 xx 24/10`

= 3 × 2.4

= 7.2 m2

∴ Area of the triangle = 7.2 sq.m

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अध्याय 7: Mensuration - Exercise 7.1 [पृष्ठ २५२]

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सामाचीर कलवी Mathematics [English] Class 9 TN Board
अध्याय 7 Mensuration
Exercise 7.1 | Q 1. (ii) | पृष्ठ २५२

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