Mark+with+degrees
131Slide rule — For other uses, see Slide rule (disambiguation). A typical ten inch student slide rule (Pickett N902 T simplex trig). The slide rule, also known colloquially as a slipstick,[1] is a mechanical analog computer. The slide rule is used primarily for …
132Depth of field — The area within the depth of field appears sharp, while the areas in front of and beyond the depth of field appear blurry …
