Find the angles of triangle ABD in triangle ABC with right angle C, if angle CBD is 20 degrees.
June 2, 2021 | education
| 1. We calculate the degree measure ∠АВD, taking into account that the bisector ВD divides ∠В into two equal angles:
∠АВD = ∠СВD = 20 °.
2. ∠В = ∠АВD + ∠СВD = 20 ° + 20 ° = 40 °.
3. We calculate the degree measure ∠A, taking into account that the total value of the angles of the triangle ABC is 180:
∠ВАD = 180 – ∠В – ∠С = 180 ° – 40 ° – 90 ° = 50 °.
4. Calculate the degree measure ∠ADB:
∠ADB = 180 – ∠ABD – ∠A = 180 ° – 20 ° – 50 ° = 110 °.
Answer: the angles of the triangle ABD – ∠ADB = 110 °, ∠ВАD = 50 °, ∠ABD = ∠СВD = 20 °.
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