Wave-formed ripple Wave-formed ripple In sedimentology, wave-formed ripples or wave-formed ripple marks are a feature of sediments (sandstones, limestones, siltstones) and dunes. These ripple marks are often characterised (and thus distinguished from current ripples) by symmetric cross sections and long relatively straight crests, which may commonly bifurcate. Commonly, these crests can be truncated by subsequent flows. Their wavelength (periodicity) depends on the sediment grain size, water depth and water-particle orbits in the waves. On tidal flats the pattern of wave-formed ripples may be complicated, as a product of changing depth and wind and tidal runoff directions. Symmetrical ripples are commonly found in
Distance between two straight lines Distance between two straight lines The distance between two straight lines in the plane is the minimum distance between any two points lying on the lines. In case of intersecting lines, the distance between them is zero, because the minimum distance between them is zero (at the point of intersection); whereas in case of two parallel lines, it is the perpendicular distance from a point on one line to the other line. Because the lines are parallel, the perpendicular distance between them is a constant, so it does not matter which point is chosen to measure the distance. Given the