Question

Дано:AD параллельно BC,AB=BC,угол ABC=140°.Найти угол ACB. Помогите)спасибо)

Answer 1

180°-140°=40° это сумма углов при основании,
так как ab=bc, треугольник abc-равнобедренный
след-но углы при основании равны, значит угол acb=cab=40:2=20°
угол acb=20°

Answer 2

Given Information:

We are given that AD is parallel to BC, AB = BC, and angle ABC = 140°. We need to find the measure of angle ACB.

Solution:

To find the measure of angle ACB, we can use the fact that the sum of the angles in a triangle is 180°. Since AD is parallel to BC, angle ABC and angle ACB are alternate interior angles and therefore congruent.

Let's denote the measure of angle ACB as x. Since angle ABC = 140°, we can write the equation:

x + 140° + x = 180°

Simplifying the equation, we have:

2x + 140° = 180°

Subtracting 140° from both sides of the equation, we get:

2x = 40°

Dividing both sides of the equation by 2, we find:

x = 20°

Therefore, the measure of angle ACB is 20°.

Conclusion:

The measure of angle ACB is 20°.