(1) ∠x を求めなさい.
60° A 31° B 26° C x D E |
(2) ∠x を求めなさい.
35° x 30° 55° |
(3) ∠x を求めなさい.
65° A x B 26° C 116° D E |
(4) ∠x を求めなさい.
72° 37° x 31° |
(1) ∠x を求めなさい.
60° A 31° B 26° C x D E ∠BEC = 60 + 31 = 91 ∠BDCは△DCEの頂点Dにおける外角だから∠BDC = ∠C+∠BEC ∠BDC = 26+91 = 117 |
(2) ∠x を求めなさい.
35° x 30° 55° 対頂角 = 180−(∠x+30) = 180−(35+55) ∠x = 60 |
(3) ∠x を求めなさい.
65° A x B 26° C 116° D E よって,∠CED = ∠BDC − ∠C = 116 − 26 = 90 ∠CEDは△ABEの頂点Eにおける外角だから∠CED = ∠A+∠B ∠CED = ∠A + ∠x = 90 よって,∠x = 25 |
(4) ∠x を求めなさい.
72° 37° x 31° 対頂角 = 180−(∠x+37) = 180−(72+31) ∠x = 66 |