Sine Cosine Functions

Math 30A Prerequisite Skills

Prerequisite Skills

Sine Law

The Pythagorean Theorem is useful for right triangles. For other triangles, the Sine Law allows us to:

calculate the length of a side when the angle opposite the side and another side and angle opposite that side are known.
calculate the size of an angle when the side opposite the angle and another side and angle opposite that side are known.

Cosine Law

The Pythagorean Theorem is useful for right triangles. For other triangles, the Cosine Law allows us to:

calculate the length of a side when the lengths of the other sides and the angle opposite the unknown side are given.
the size of an angle when the lengths of all 3 sides of a triangle are given..

Use the Pythagorean theorem to calculate the length of a third side when the other two sides of a right angle are known. The Distance Formuila uses the Pythagorean Theorem on the Cartesian plane.

Download the newest java version if the applet fails to launch.

Angles can be measured with a protractor. As angles are created they will be classified as:

acute: less than 90^o
right: 90^o
obtuse: greater than 90^o,but less than 180^o
straight: : 180^o

Isosceles triangles have two congruent sides/angles. Scalene triangles have no congurent sides/angles. Equilateral triangles have 3 congruent sides/angles.

The sum of angles in a triangle is 180^o.

Two angles that form a line are supplementary (sum is 180^o).

Triangle Types:	Characteristics
Acute	all angles are less than 90^o
Right	one angle is 90^o
Obtuse	one angle is greater than 90^o
Scalene	no two sides are congruent
Isosceles	two sides are congruent. Note: The sides opposite the equal angle are also equal.
Equilateral	all three sides are congruent. Note: The sides opposite the equal angle are also equal.

Click the applet once to activate: Use the applet to create:

scalene triangle: no two sides are inscribed in the same circle.
isosceles triangle: exactly two sides are inscribed in the same circle.
equilateral triangle: Two angles are inscribed in different circles and the third angle is inscribed in both circles at one of the two intersection poinst of the two circles. Note: when you click on one side, the other two angles will be inscribed in different circles.

Download the newest java version if the applet fails to launch.

Math 30A Prerequisite Skills

Comments to: Jim Reed - Homepage