TRIG THE EASY WAY Trig functions To remember

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 HYPOTENUSE OPP. LEG ADJ. LEG

TO FIND A MISSING SIDE 21 ? 42°

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

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

solution ü ü ü Sin 42° = x / 21. 6691 = x / 21 X = (. 6691) (21) X= 14. 0511 X= 14. 1

TO FIND A MISSING ANGLE 8 ? 15

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

PROCESS AND SOLUTION l Determine the function ----> Tangent l Write the equation -----> Tan D = 8 / 15 l Solve the equation -----> Tan D =. 5333 Note : you must use the inverse of tangent to find the angle: -1 tan or arctan on your calculator. ‹D = tan-1(0. 5333) ‹D = 28. 072487 ‹D = 28º