Mathematics Question and Solution
Let AB equal 1 unit.
(1/sin60) = (a/sin20)
a = 0.39493084363 units.
a is BC.
(1/sin60) = (b/sin100)
b = 1.1371580426 units.
b is AC.
(1.1371580426/sin110) = (c/sin10)
c = 0.21013831273 units.
c is CD.
(BD)² = 0.21013831273²+0.39493084363²-2*0.21013831273*0.39493084363cos120
BD = 0.53208888623 units.
(0.53208888623/sin120) = (0.21013831273/sind)
d = 20°
d is angle CBD.
Therefore the required angle x is;
100-d
x = 100-20
x = 80°
