ABC is an isosceles triangle BC base angle A = 55 ° BD height, which is equal to the angle DBC.

It is known:

ABC – isosceles triangle;

BC – base;

Angle A = 55 °;

BD – height.

Find the angle DB.

1) Since triangle ABC is isosceles, it means that angle B = angle C.

Angle A + angle B + angle C = 180 °;

2 * angle С + 55 ° = 180 °;

2 * angle С = 180 ° – 55 °;

2 * angle С = 125 °;

Angle C = 125 ° / 2;

Angle C = 62.5 °.

2) Consider a right-angled DBC triangle with a right angle D.

There are 2 known angles. Find the third corner, that is, the DBC angle.

DBC angle = 180 ° – 55 ° – 90 ° = 90 ° – 55 ° = 90 ° – 50 ° – 5 ° = 40 ° – 5 ° = 35 °.

This means that the angle of the internal combustion engine = 35 °.