# Find a larger angle of the isosceles trapezoid ABCD if the diagonal of the AC forms with the base AD and the side AB

Find a larger angle of the isosceles trapezoid ABCD if the diagonal of the AC forms with the base AD and the side AB the angles of 25 ° and 40 °, respectively By the property of an isosceles trapezoid, the angles at the base are equal. Then ∠CDA = ∠BAD = 40 ° + 25 ° = 65 °.
AD || BC (by the definition of a trapezoid), then side AB can be considered as secant to these parallel lines.
Therefore, ∠DAB + ∠ABC = 180 ° (because these angles are internal one-sided) => ∠ABC = 180 ° -∠DAB = 180 ° -65 ° = 115 °.
∠BCD = ∠DAB = 115 ° (by the property of an isosceles trapezoid).
Therefore, these are the larger angles of the trapezoid.
Answer: a larger trapezoid angle = 115 ° Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.