The document discusses trigonometry concepts including: 1. Using trigonometric functions to solve for missing sides or angles of right triangles. 2. The concept of significant digits and how to determine the number of significant digits in measurements. 3. Examples of using trigonometric functions and the concept of significant digits to solve problems involving right triangles and their angles and side lengths.

1. Objectives:
1. Use trig to solve for missing sides or
angles of a right triangle.

2. What are Significant Digits?
The “interesting” or “important” digits.
Examples:
3.14159 has six significant digits
1000 has one
1000.0 has five
0.00035 has two
1006 has four

3. Basic Rules:
All nonzero digits are significant.
All zeros between significant digits are
significant.
All zeros to the right of both the
decimal point and all non-zero
significant digits are significant.

4. Rounding
Round each # to 3 significant digits:
742,396
0.07284
231.45

5. Now Triangles!
Remember SOH-CAH-TOA ??
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6. Example 1:
Find the value of b to three significant
digits.

7. You Try!
A 20 ft ladder is leaned against a
house at an angle of 70° with the
ground. Find:
The distance from the base of the
house to the foot of the ladder.
The height reached by the ladder.
(Round to 3 significant digits)

8. Example 2:
In ΔABC, <A = 90°, a = 29 and b = 21.
Find <B to the nearest tenth of a
degree.

9. You Try!
A tower is 553 m high. An observer at
point A, 100 m from the base of the
tower, sees the top of the tower with
angle of elevation <A. Find this angle
measure to the nearest tenth of a
degree.

10. Example 3:
A triangle has side lengths 8, 8, and 4.
Find the measures of the angles to the
nearest tenth of a degree.

11. You Try!
A rhombus with perimeter 40 cm has a
70° angle. Find the lengths of its
diagonals.