As shown in the figure: in rectangular ABCD, ab = 2ad, e is a point on CD, and AE = AB, then ∠ CBE is equal to______ .

As shown in the figure: in rectangular ABCD, ab = 2ad, e is a point on CD, and AE = AB, then ∠ CBE is equal to______ .

∵ AB = 2ad, AE = AB, ∵ AE = 2ad, ∵ AED = 30 °, ∵ in rectangular ABCD, ab ∥ CD, ∵ BAE = ∠ AED = 30 ° in △ Abe, ∵ AE = AB, ∵ Abe = 12 (180 ° - BAE) = 12 × (180 ° - 30 °) = 75 ° in △ Abe, ∵ CBE = ∠ ABC - ∠ Abe = 90 ° - 75 ° = 15 °. So the answer is: 15 °