Curve surface of cone = rl; 1 = slant height. Curve surface of frustum of cone = π (r1+r2)l Curve surface of segment of sphere = 2πrh; h = height of segment. Curve surface of spherical zone = 2πrh; h = height of h, perpendicular height; A, & areas of ends. radius of base, h, the height, of the segment; or r being radius of sphere; h, height of segment. Volume of zone of sphere = h {h3+3 (p2+q3)} 6 P, q being radii of ends. FORMULE IN CO-ORDINATE GEOMETRY. Equation to straight line, axes rectangular, y = mx + c. Equation to straight line, axes rectangular, through (x', y′), y—y' = m (x − x′). Equation to straight line, axes rectangular, through Equation to straight line, axes rectangular, through (x', y') & L to y=mx+c; y—y' = H m - (x — x′). Equation in terms of the intercepts of the axes, a sin a sin 1 ·a)' x + c. mm1 = 1. Length of perpendicular, from (x, y) upon y = mx + c = ± y' - mx'. -c √1+ m2 Length of perpendicular, from (x', y') upon x cos a + y sin a—p‚=x' cos a+y' sin a-p. Equation to circle, origin anywhere, (x-a)2+(y—b)2 = r2. Equation to circle, origin at centre, x2 + y2 = r2. Equation to tangent at (x', y'), xx' + yy' = r2; y = mx + r√ 1 + m22. Equation to normal at (2′, y'), y = 2 (x', .x. Equation to chord of contact, xh + yk = r2. Equation to parabola, origin at vertex, y2 = 4ax. Equation to tangent at (x', y), yy'=2a (x+x'); y=mx+· Equation to normal at (x', y'), y-y' or y = mx-2am-am3. a m Equation to tangent at (x', y'), a2yy' +b2xx'=a2b2, or y = mx + √ a2 m2 + b2. Equation to tangent at (x', y'), a2yy' — b2xx' — — a2b2, = Equation to normal at (x', y'), y-y' = Polar equation to straight line, p = r cos (0—a). Polar equation to circle, c2 = r2 + 12 - 2lr cos (6—a). Polar equation to parabola, focus, the pole, r = 2a 1 + cos 0 |