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MathNet 2013 Question 94

Math Olympiad Vault · MathNet 2013

Question 94

Pentagon $A B C D E$ is given with the following conditions:
(a) $\angle C B D + \angle D A E = \angle B A D = 45^{\circ}, \angle B C D + \angle D E A = 300^{\circ}$
(b) $\frac{B A}{D A} = \frac{2 \sqrt{2}}{3},\ C D = \frac{7 \sqrt{5}}{3}$, and $D E = \frac{15 \sqrt{2}}{4}$
(c) $A D^{2} \cdot B C = A B \cdot A E \cdot B D$

Compute $B D$.

Supplemental illustration (AI-generated; triangle ABD only):

Question illustration