In a triangular field having sides 30m, 72m and 78m, the

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In a triangular field having sides 30m, 72m and 78m, the length of the altitude to the side measuring 72m is :

Using Rule 1,

Semi-perimeter,

S =	30 + 72 + 78	= 90
	2

Area of triangle ABC = √s(s - a)(s - b)(s - c)
= √90(90 - 30)(90 - 72)(90 - 78)
= √90 × 60 × 18 × 12
= 1080 m²
If the altitude AD be h metre, then,

	1	× Base × height = 1080
	2

⇒	1	× 72 × h = 1080
	2

h =	1080	= 30 metre
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