(1)∠BGC=180°-(∠EBC+∠FCB)
BE,CF角B和角C的平分线,∠EBC、∠FCB分别=角B和角C的1/2
(2)∠BGC=180°-(∠EBC+∠FCB)
角A=180°-(角B+角C)=180°-2(∠EBC+∠FCB)
-2(∠EBC+∠FCB)=角A-180°
(∠EBC+∠FCB)=90°-角A/2
角BGC=180°-(∠EBC+∠FCB)=180°-(90°-角A/2)=90°+角A/2
(1)∠BGC=180°-(∠EBC+∠FCB)
BE,CF角B和角C的平分线,∠EBC、∠FCB分别=角B和角C的1/2
(2)∠BGC=180°-(∠EBC+∠FCB)
角A=180°-(角B+角C)=180°-2(∠EBC+∠FCB)
-2(∠EBC+∠FCB)=角A-180°
(∠EBC+∠FCB)=90°-角A/2
角BGC=180°-(∠EBC+∠FCB)=180°-(90°-角A/2)=90°+角A/2