Hamilton's Math To Build On - copyright 1993

Finding the Angle Using the Functions Table

About Math To Build On || Contents || On to Complementary Angles || Back to Two Sides Known || Glossary

* Finding the Angle Using the Functions Table

Below is a sample of a functions table found farther on in the book. Notice that the table includes all six functions, plus something you will study later, radians.

The functions table is read in two directions:

For 0° to 45°, read top to bottom

For 45° to 90° , read bottom to top.

Notice that angles are shown on both sides of the chart. When reading down the column for 0° through 45° , use the function names listed at the top of the table. When reading up the table for 45° through 90° , use the function names at the bottom. It is important that you note the difference.

We worked with the 3-4-5 right triangle earlier. Let's use the same angle for an example again. Below are the functions for the reference angle of that 3-4-5 right triangle. Notice that Sin = 0.6000.

Look at the functions table on pages 214 and 215. To find the degrees of the reference angle, go down the sine column until you get to the number closest to 0.6000. The closest you will find is 06018. Reading the angle to the left of that number gives you the degrees of the reference angle, 37° .

Notice that you could have used any of the functions to find this angle.

On to Complementary Angles

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16 September 1995
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