Mathematics Question and Solution
Observing cosine rule.
a² = 12²+4²-2*12*4cos60
a = 10.5830052443 units.
Observing cosine rule.
b² = 3²+12²-2*3*12cos120
b = 13.7477270849 units.
Observing cosine rule.
10.5830052443² = 13.7477270849²+7²-2*7*13.7477270849cosc
192.4681791886cosc = 126
c = acos(126/192.4681791886)
c = 49.106605351°
d = 2c
d = 98.213210702°
e = ½(10.5830052443)
e = 5.2915026222 units.
Therefore, r, radius of the circle is;
sin49.106605351 = 5.2915026222/r
r = (5.2915026222/sin49.106605351)
r = 7 units.
