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प्रश्न
In the adjoining figure, ΔABC is a right-angled triangle in which ∠B = 900, ∠300 and AC = 20cm. Find (i) BC, (ii) AB.
उत्तर
From the given right-angled triangle, we have:
`(BC)/(AC) = sin 30^0`
⇒`(BC)/20=1/2`
⇒BC = `20/2 = 10cm`
Also, `(AB)/(AC) = cos 30^0`
⇒`(AB)/20=sqrt(3)/2`
⇒`AB = (20xxsqrt(3)/2) = 10sqrt(3) cm`
∴ BC = 10cm and AB = 10`sqrt(3)` cm
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