Find coordinates within a given radius

-- 60       => minutes/degree
-- 1.1515   => statute miles/nautical mile
-- 1.609344 => km/mile
-- Town table is where your latitude and longitude information are stored

DECLARE @Latitude                       FLOAT = 40.646667,
        @Longitude                      FLOAT = -83.608611,
        @MinutesPerDegree               FLOAT = 60.0,
        @StatuteMilesPerNauticalMile    FLOAT = 1.1515,
        @KilometersPerMile              FLOAT = 1.609344,
        @multiplier                     FLOAT = @MinutesPerDegree * @StatuteMilesPerNauticalMile * @KilometersPerMile

SELECT * FROM (
    SELECT
        TownID,
        Name,
        (((
            ACOS(
                SIN((@Latitude * pi() / 180)) *
                SIN((Latitude  * pi() / 180)) +
                COS((@Latitude * pi() / 180)) *
                COS((Latitude  * pi() / 180)) *
                COS((@Longitude - Longitude) * pi() / 180))
            ) * 180 / pi()
        ) * @multiplier
    ) AS DistanceKM
    FROM Town
) t
WHERE Distance <= 75