數學 triangles

1. x=110⁰
y = 180-110-25 = 45⁰

2014-02-22 18:17:16 補充：
cos∠P = 6/10

∠P = 53.13⁰
b = 53.13⁰

RQ² = 10²-6²=64
RQ=8
a=8

2014-02-22 18:19:03 補充：
3
∠ACD = 180 - 35 - 25 = 120⁰

2x = 120⁰

x = 60⁰

y+3=12

y=9