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Question
ΔABC is right angled at A (see the given figure). AD is perpendicular to BC. If AB = 5 cm, BC = 13 cm and AC = 12 cm, Find the area of ΔABC. Also find the length of AD.
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Solution
Area = `1/2 xx "Base" xx "Height"`
Area of ΔABC = `1/2 xx "AB" xx "AC"`
= `1/2 xx 5 xx 12`
= 30 cm2
Also, area of triangle = `1/2 xx "AD" xx "BC"`
30 = `1/2 xx "AD" xx 13`
`(30 xx 2)/13` = AD
AD = 4.6 cm
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