(1) ∠x を求めなさい.
x A 36° B 29° C 135° D E |
(2) ∠x を求めなさい.
37° 47° 40° x |
(3) ∠x を求めなさい.
65° A 28° B 31° C x D E F |
(4) ∠x を求めなさい.
50° A 30° B x C 111° D E |
(1) ∠x を求めなさい.
x A 36° B 29° C 135° D E よって,∠CED = ∠BDC − ∠C = 135 − 29 = 106 ∠CEDは△ABEの頂点Eにおける外角だから∠CED = ∠A+∠B ∠CED = ∠x + ∠B = 106 よって,∠x = 70 |
(2) ∠x を求めなさい.
37° 47° 40° x 対頂角 = 180−(∠x+37) = 180−(47+40) ∠x = 50 |
(3) ∠x を求めなさい.
65° A 28° B 31° C x D E F ∠CFB = 65 + 31 = 96 ∠BDCは△BDFの頂点Dにおける外角だから∠BDC = ∠B+∠CFB ∠BDC = 28+96 = 124 |
(4) ∠x を求めなさい.
50° A 30° B x C 111° D E ∠BEC = 50 + 30 = 80 ∠BDCは△DCEの頂点Dにおける外角だから∠BDC = ∠C+∠BEC ∠C = ∠x = ∠BDC − ∠BEC = 31 |