Mathematics Question and Solution
Let BC be 1 unit.
a = 180-60-20-40-10
a = 50°
a is angle ACB.
Observing Sine Rule.
(b/sin50) = (1/sin(60+20))
b = 0.7778619134 units.
b is AB.
c = 180-40-60
c = 80°
c is angle ADB.
Observing Sine Rule.
(0.7778619134/sin80) = (d/sin60)
d = 0.6840402867 units.
d is BD.
Observing Cosine Rule.
e² = 0.6840402867²+1²-2*0.6840402867*1cos10
e = 0.3472963553 units.
e is CD.
Therefore, calculating the required angle alpha (angle BCD). Let it be f.
It implies, observing Sine rule.
(0.3472963553/sin10) = (0.6840402867/sinf)
f = 20°
Therefore, the required angle alpha (angle BCD), f is;
20°
