I need help with this Trig formula

A camera is mounted on a tripod 4 feet high at a distance of 10 feet from Frank, who is 6' tall. If the camera lens has angles of depression and elevation of 20 degrees, will Frank's feet and head be seen by the lens? If not, how far back will the camera need to be moved to include Frank's feet and head?

I can't figure out the formula to this.

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