1. Finding the missing side of triangle∆ ABC
• We are given two sides b = 4 and c = 8 with an angle A =46° between the two sides .
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• we are to find side a =?? and angle B and C
2. Apply the Cosine rule of triangle
a^2 = b^2 + c^2 -2bc Cos A
a^2 = 4^2 + 8^2 -2*4*8 Cos46°
a^2 = 16 +64 -64(0.695)
a^2 = 80 -44.46
a^2 =35.54
a = (√35.54)
a = 5.962......( round off to the nearest tenth)
Therefore , a = 6
3. solving angle B
tan B = opp/adj = b/a = 4/6 =0.66666
tan^-1( 0.66666) = angle B T
Therefore, angle B = 33.68 ≈34°
4 . Solving Angle C
angle A + angle B + angle C = 180° ( angles of a triangle add up to 180°)
46 + 34 + angle C = 180°
angle C= 180 ° -80°
Therefore, angle C = 100°
