Trigonometry · Superchallenge problem

A vertical pole $10$ m tall stands on level ground, $4$ m from a long vertical wall (measured perpendicular to the wall). The sun is $30^\circ$ above the horizon. Seen from above, the sun's rays head toward the wall at an angle of $60^\circ$ to the perpendicular from the pole to the wall. The pole's shadow runs along the ground to the wall and then climbs the wall. How high up the wall does the shadow reach, in metres?