Triangle Formulas
Right Triangle Side a and b are at a 90 degree angle a = vertical side b = horizontal side c = longest side or hypotenuse Solve for: Formula Hypotenuse c sq.rt.(a2 + b2) Side a sq.rt.(c2 + b2) Side b sq.rt.(c2 + a2) Area A 1/2ab		Oblique Triangle The sides are any length and at any angle to each other a = right side b = longest side or base c = left side h = height (base b to junction of ac and 90 degrees to b) s = sides Solve for: Formula Area A 1/2bh Area A if the abc are known s = 1/2(a + b + c) A = sq.rt.[s(s-a)(s-b)(s-c)]

Circular Formulas
Circle A = Area d = diameter p = perimeter or circumference pi = 3.1416 pi/4 = .7854 r = radius Solve for: Formula perimeter p (pi)d perimeter p 31/7 d (approximately) perimeter p 2(pi)r diameter d p/pi diameter d 7/22 p (approximately) diameter d 1.128(sq.rt.(A)) radius r p/2(pi) radius r .5642(sq.rt.(A)) Area A (pi)d2/4 = .7854 d2 Area A (pi)r2 = 3.1416 r2		Helix d = diameter of helix l = lenght of one turn of helix t = pitch, or rise in 1 turn n = number of turns pi2 = 9.8696 Solve for: Formula lenght of one turn sq.rt.(pi2)d2 + t2 pitch or rise one turn t sq.rt.(l2) - pi2 d2 Total lenght or nl n[sq.rt.(pi2 d2 + t2)]