In the rectangular trapezoid ABCD, AD / / BC, ∠ a = 90 ° ad = 21cm BC = 24cm E.F. moves from A.C. to D.B. at the same time at 1cm / s and 2cm / s. when they move for how long, is the trapezoid efcd a rectangular trapezoid?

In the rectangular trapezoid ABCD, AD / / BC, ∠ a = 90 ° ad = 21cm BC = 24cm E.F. moves from A.C. to D.B. at the same time at 1cm / s and 2cm / s. when they move for how long, is the trapezoid efcd a rectangular trapezoid?

Let the trapezoid efcd be a right angle trapezoid after moving T seconds
According to the meaning of the title: AE = BF, and AE = t after e moves T seconds, CF = 2T after f moves T seconds;
BF = bc-cf
∴t＝24－2t
Solution: T = 8 (seconds)

In the rectangular trapezoid ABCD, AD / / BC, ∠ a = 90 ° ad = 21cm BC = 24cm E.F. moves from A.C. to D.B. at the same time at 1cm / s and 2cm / s. when asked how long they move, the trapezoid efcd is isosceles trapezoid?

Draw a diagram and set X seconds. The lower base is 6cm more than the upper base, and 21-x + 6 = 2x --- x = 9

In the quadrilateral ABCD, ∠ bad = 90 ° AB = ad, if the area of quadrilateral ABCD is 1cm & # 178;, then the length of AC is? Cm

Square, root 2