If two angles of a triangle are 30o each and th... - JAMB Mathematics 1993 Question
If two angles of a triangle are 30o each and the longest side is 10cm. Calculate the length of each of the other sides
A
5cm
B
4cm
C
3√3 cm
D
10\(\frac{3}{3}\)cm
correct option: d
102 = 2x2 - 2x2 cos 120o (Cosine rule)
100 = 242 - 2x2 - 2x2 x -\(\frac{1}{2}\)
100 = 3x2 + x2
= 3x2
x = \(\sqrt{\frac{100}{3}}\)
= \(\frac{10}{\sqrt{3}}\) x \(\frac{3}{\sqrt{3}}\)
x = 10\(\frac{3}{3}\)cm
100 = 242 - 2x2 - 2x2 x -\(\frac{1}{2}\)
100 = 3x2 + x2
= 3x2
x = \(\sqrt{\frac{100}{3}}\)
= \(\frac{10}{\sqrt{3}}\) x \(\frac{3}{\sqrt{3}}\)
x = 10\(\frac{3}{3}\)cm
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