In the right-angled triangle MBC the height of the air pressure is drawn. BC leg = 18 cm, CBD angle is 60 degrees.

In the right-angled triangle MBC the height of the air pressure is drawn. BC leg = 18 cm, CBD angle is 60 degrees. Find the length of the BD height.

Given: ΔMBC – rectangular; BD – height; BC = 18 cm and ⦟CBD = 60 °
Find: BD =? cm
Solution: Consider the ΔBCD:
BD – height (by condition) → ⦟CDB = 90 ° → ΔBCD – rectangular.
⦟CBD = 60 ° (by condition) → ⦟BCD = 180 ° -90 ° -60 ° = 30 ° (by the theorem on the sum of the angles of a triangle) → BD = 0.5BC (a leg lying opposite an angle of 30 ° is equal to half the hypotenuse ) → BD = 0.5 * 18 = 9 cm
Answer: BD = 9 cm