The measurement of the required depth of a rear yard or the required width of an interior side yard shall be horizontal and inward from the lot line at a right angle. Where the side lot lines converge, or nearly converge, a line ten feet long within the lot, parallel to the front lot line and at a maximum distance therefrom shall be deemed to be the rear lot line for the purposes of this section. (Prior gen. code § 8-60.35)