Explanation:
remember answer 2.
3. I answered already in my other answer.
remember, the diagonals split the angles in half.
so,
d1 = 50°
4. the tangent ratio is sine/cosine (that is the definition of tangent).
c2 = 40°
sin(40) × 5 = OD (half of BD)
cos(40) × 5 = OC
the tangent ratio is
(sin(40) × 5) / (cos(40) × 5) = sin(40)/cos(40) = OD/OC =
≈ 3.2 / 3.8 = 1.6/1.9 =
= 0.842105263...
control : tan(40) = 0.839099631... close enough (we used round numbers with 3 2 and 3.8 - see again 1. and 2.).