1. [non right-angled triangles]
Pythagoras
[non right-angled triangles]
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2. Non-right angled trianglesC C C
“Hypotenuse”
“Hypotenuse”
Hypotenuse B A A B A B
RIGHT ANGLED
OBTUSE TRIANGLE
ACUTE TRIANGLE
The hypotenuse squared is equal to the sum of the squares of the other two sides
The hypotenuse squared is greater than the sum of the squares of the other two sides
The hypotenuse squared is less than the sum of the squares of the other two sides
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3. Non-right angled trianglesC
OBTUSE TRIANGLE 92 42
+ 72 9 81 7 16
+ 49 81
> 65 A B 4
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4. Non-right angled trianglesC
ACUTE TRIANGLE 82 62
+ 72 64 36
+ 49 6 8 64
< 85 A B 7
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5. Determine what type each of these triangles is, given the lengths of their sides:
8, 10, 13
9, 11, 13
9, 40, 41
Longer side is 13
Longer side is 13
Longer side is 41
132 = 169
132 = 169
412 = 1681 = = = = = =
164
202
1681
OBTUSE TRIANGLE
ACUTE TRIANGLE
RIGHT-ANGLED TRIANGLE
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6. Classify the following triangle triples
Classify the following triangle triples* into acute, right-angled and obtuse.
*lengths of the 3 sides of triangles
(2,4,5)
(3,4,5)
(1,3,5)
(5,12,13)
(7,20,25)
(11,21,24)
(7,24,25)
(9,11,15)
(9,14,19)
(10,17,25)
(8,15,17)
(7,20,25)
(11,21,30)
(17,24,35)
(20,21,29)
(18,35,50)
(9,13,20)
(15,36,40)
(9,40,41)
(15,20,24)
(11,60,61)
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