Determine the nature of the triangle ABC, the measurements of his angles of which are respectively, a, b, c such as:
Hello dhiabIt is isosceles, with .
This may be proved by trigonometry formulae:or, using the Sine Rule, which gives:
, since
, since and both lie between and
and then considering the attached diagram:
is the foot of the perpendicular from to . ThenGrandad
is the mid-point of
is isosceles with .