|
ISOSCELES RIGHT TRIANGLE
One of the special right triangles which we deal with in geometry is an isosceles right triangle.
These triangles are also known as 45-45-90 triangles (so named because of the measures of their angles)
PYTHAGOREAN THEOREM
in a right triangle, the square of the measure of the hypotenuse equals the sum of the squares
of the measures of the two legs. This theorem is normally represented by the following equation: a2
+ b2 = c2, where c represents the hypotenuse.
|
 |
|
Postulates
SSS Postulate If
three sides of one triangle are congruent to three sidesof another triangle, then the two triangles are congruent.
SAS Postulate If two sides and the included angle of one triangle arecongruent to two sides and the congruent angle of another triangle,
then the two trianglesare congruent.
ASA Postulate If two angles and the included side of one triangle arecongruent to two angles and the included side of another triangle,
then the two trianglesare congruent.
AA Postulate If two angles of one triangle are congruent to twoangles of another triangle, then the two triangles are similar.
Triangles always have an angle sum of 180 degrees.
There can never be more than 2 obtuse triangle.
And it can never have two right angles.
|
|
|
|
RIGHT TRIANGLE
There's another kind of special right triangle which we deal with all the time. These
triangles are known as 30-60-90 triangles (so named because of the measures of their angles).
TRIGONOMETRIC RATIOS
sine of angle A = (measure of opposite leg)/(measure of hypotenuse). In
the figure, the sin of angle A = (a/c).
cosine of angle A = (measure of adjacent leg)/(measure
of hypotenuse). In the figure, the cos of angle A = (b/c).
tangent of angle A =
(measure of opposite leg)/(measure of adjacent leg). In the figure, the tan of angle A = (a/b)
You could also use this:
S in
O pposite
H ypotenuse
C osine
A djacent
H ypotenuse
T angent
O pposite
A adjacent
|
|
|
|
|
