The figure shows a quadrilateral ABCD with
angles BAD, BAC, BCA, and ACD equal to 90, 22.5, 30, and 15
degrees, respectively, Find the measure of angle ABD.
*This entry contributed by Abdilkadir ALTINTAS and Ayhan YANAGLIBAS)*.
When asked how he developed his mathematical abilities so rapidly, he replied "by studying the masters, not their pupils." Abel, Niels Henrik. 1802-1829. |