As shown in the figure, in the trapezoidal ABCD, ad ‖ BC, ∠ bad = 90 ° and ∠ d = 45 °, EF is the vertical bisector of CD, and the perpendicular foot is e, The moving point t (m, n) represents the torch position, and the torch starts to pass from the m point 10 meters away from Beijing road The above explanation is wrong and should be correct As shown in the figure, in trapezoidal ABCD, ad ‖ BC, ∠ bad = 90 ° and ∠ d = 45 °, EF is the vertical bisector of CD, the perpendicular foot is e, EF intersects ad with m, and the extension line of Ba intersects F. Verification: BF = ad

As shown in the figure, in the trapezoidal ABCD, ad ‖ BC, ∠ bad = 90 ° and ∠ d = 45 °, EF is the vertical bisector of CD, and the perpendicular foot is e, The moving point t (m, n) represents the torch position, and the torch starts to pass from the m point 10 meters away from Beijing road The above explanation is wrong and should be correct As shown in the figure, in trapezoidal ABCD, ad ‖ BC, ∠ bad = 90 ° and ∠ d = 45 °, EF is the vertical bisector of CD, the perpendicular foot is e, EF intersects ad with m, and the extension line of Ba intersects F. Verification: BF = ad

Even cm
It is an isosceles right triangle
E is the midpoint of CD, me is vertical, CD = > DCM is also isosceles right triangle
Cm vertical ad, CM = DM
Ba vertical ad = > AMCB is rectangular = > AB = cm = DM
AB vertical ad, ∠ AMF = ∠ EMB = 45 ° = > AFM is also isosceles right triangle = > am = AF
So BF = Ba + AF = DM + am = ad