8.3 Trigonometry

• Trigonometric Ratios– Similar right triangles have equivalent ratios for

their corresponding sides.

Trigonometric Ratios

Using a Trigonometric Ratio to Find Distance• In 1990, the Leaning Tower of Pisa was closed to the public due to safety

concerns. The tower reopened in 2001 after a 10-year project to reduce its tilt from vertical. Engineers’ efforts were successful and resulted in a tilt of 5°, reduced from 5.5°. Suppose someone drops an object from the tower at a height of 150 ft. How far FROM the base of the tower will the object land? Round to the nearest foot.

tan5150

x

150(tan5 )x

13.12329953x 13 .ft

Inverses

• If you know the sine, cosine, or tangent ratio for an angle, you can use an inverse (sin-1, cos-1, tan-1) to find the measure of the angle.– See Example 3 on p. 509

More Practice!!!!!

• Homework – Textbook p. 510 – 511 #11 – 27 ALL.