Current location - Training Enrollment Network - Mathematics courses - Start the seventh grade mathematics education edition middle school workbook 2 1 page, and make a comprehensive inquiry. Will anyone?
Start the seventh grade mathematics education edition middle school workbook 2 1 page, and make a comprehensive inquiry. Will anyone?
Make BC and DC in e.
∫AE‖BC
∴∠BAE+∠B= 180，∠C=∠AED
∫△ADE
∴∠dae+∠d+∠aed= 180 =∠DAE+∠d+∠c
∴∠bae+∠b+∠dae+∠d+∠c=∠a+∠b+∠c+∠d=360
PS: It is a theorem that the sum of the internal angles of a quadrilateral is 360. ...