what is a right triangle? it is a triangle which has an angle that is 90 degrees. the two sides that...
TRANSCRIPT
What is a right triangle?
It is a triangle which has an angle that is 90 degrees.
The two sides that make up the right angle are called legs.
The side opposite the right angle is the hypotenuse.
leg
leg
hypotenuse
right angle
CLICK!
• Wizard of OZ
• http://teachertube.com/viewVideo.php?video_id=145155
Find the length of the hypotenuse if1. a = 12 and b = 16.
122 + 162 = c2
144 + 256 = c2
400 = c2
Take the square root of both sides.
20 = c
2400 c
52 + 72 = c2
25 + 49 = c2
74 = c2
Take the square root of both sides.
8.60 = c
Find the length of the hypotenuse if2. a = 5 and b = 7.
274 c
Find the length of the leg, to the nearest hundredth, if
3. a = 4 and c = 10.42 + b2 = 102
16 + b2 = 100Solve for b.
16 - 16 + b2 = 100 - 16b2 = 84
b = 9.17
2 84b
Find the length of the missing side given a = 4 and c = 5
1. 1
2. 3
3. 6.4
4. 9
What are Pythagorean Triples?
• Three integers that make the equation a2 + b2 = c2 true are called Pythagorean Triples.
• The numbers 3, 4 and 5 are a very famous Pythagorean Triple.
a2 + b2 = c2
32 + 42 = 52
9 + 16 = 25
5, 12, 13Another common
triple
Practice: Are they Pythagorean Triples?
• 1) yes or no? 2) yes or no?
9 + 64 = 7373 = 73
Since this is true, the triangle is a right triangle!! If it was not true, it
would not be a right triangle.
Sides: , 3, and 832 + 82 = ( ) 2
7373
Pythagorean Inequality Theorem
a & b are the legs
c is the hypotenuse
a2 + b2 = c2
c
a
b
Pythagorean Inequalities:
c2 > a2 + b2 - - - Triangle is obtuse
c2 < a2 + b2 - - - Triangle is acute
Pythagorean Inequalities
The following triples represent the side lengths of a triangle. Determine whether the triangle is right, acute or obtuse.
1. 5, 9, 12
2. 7, 24, 26
3. 13, 15, 17
4. 3, 4, 5
5. 25, 25, 30
Obtuse
Obtuse
Acute
Right
Acute