1. In△PQR, PQ=PR. The angle bisector of ∠PQR meets PR at X. Given that CQXR =105°, calculate ∠QPR.
2. In △ABC, ∠ABC =22°and ∠CAB =112°. BC is produced to X and the angle ACX meets BA produced at Y. Find ∠AYC.
3. Four interior angles of a pentagon are 30°, 88°, 112° and 145°. Find the fifth angle.
數學問題!Help!
2007-04-14 1:30 am
回答 (1)
2007-04-14 2:12 am
✔ 最佳答案
Let ∠PQX=∠XQR=a, ∠PRQ=∠PQR=2a( base∠ isos△ )a+2a+105°=180°(∠ sum of △)
a =25°
∠QPR+100°=180°(∠ sum of △)
∠QPR=80°
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