Mathematics Question and Solution
a = 8+2
a = 10 units.
a is OA, the radius of the half circle.
b = 2a
b = 20 units.
b is AB, the diameter of the half circle.
c = 2+a
c = 12 units.
c is BC.
Notice.
BC = BD = 12 units.
d²+12² = 20²
d² = 400-144
d = √(256)
d = 16 units.
d is AD.
tane = 16/12
e = atan(4/3)°
e is angle ABD.
f = ½(e)
f = ½(atan(4/3))°
f is angle ABF
Therefore, the required length, BF is;
Let it be g.
cos(½(atan(4/3))) = g/20
g = 20cos(½(atan(4/3)))
g = 17.88854382 units.
Again, g is the required length, BF.
