In a quadrilateral ABCD, the acute angle A is greater than 30 degrees, and the other three angles

In a quadrilateral ABCD, the acute angle A is greater than 30 degrees, and the other three angles are equal. What values can the angle ABC take?

In order to solve this problem, you need to know the properties of the quadrangle and draw a picture to make it easier to understand the situation. If A> 30 °, then: 30 ° <A <90 °, the remaining three angles will remain less than 330 ° (but more than 270 °), because (the sum of the angles of a 4-gon = 360 °), then:

360 ° – 90 ° <B + C + D <360 ° – 30 °.

270 ° <3 * B <330 °.

90 ° <B <110 °.

Therefore, our answer is: 90 ° <B <110 °.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.