TRIG – THE EASY WAY

Trig functions To remember the trigonometry functions, use the memory aid: Soh Cah Toa The first letter of each aid represents the function. The last two letters indicates the ratio of sides needed to calculate the function. Soh --> Sine = opposite/hypotenuse Cah --> Cosine = adjacent/hypotenuse Toa --> Tangent = opposite/adjacent We can use trigonometry functions to determine: • one acute angle if you know two sides • one of the sides if you know an acute angle and one side

HYPOTENUSE, OPP. LEG, & ADJ. LEG

TO FIND A MISSING SIDE 21 ? 42°

THE PROCESS Determine what trig function to use Set up the equation that solves the situation Solve the equation and round answer appropriately 21 ? 42°

DETERMINING THE FUNCTION hypotenuse 21 ? Opp 42° Opposite / hypotenuse >>>>>>>>> SINE

solution Sin 42° = x / 21 .6691 = x / 21 X = (.6691) (21) X= 14.0511

TO FIND A MISSING ANGLE 8 ? 15

DETERMINE THE FUNCTION. OPPOSITE 8 ? 15 ADJACENT OPPOSITE / ADJACENT >>>>>>>>> TANGENT

PROCESS AND SOLUTION ‹D = tan-1(0.5333) ‹D = 28.072487 ‹D = 28º Determine the function ----> Tangent Write the equation ----------> Tan D = 8 / 15 Solve the equation ---------> Tan D = .5333 Note : you must use the inverse of tangent to find the angle: tan-1 or arctan on your calculator. ‹D = tan-1(0.5333) ‹D = 28.072487 ‹D = 28º