Lesson 1: Pythagorean Theorem - Determining if a Triangle Has a Right Angle Example 2


EXAMPLE 2

Is the triangle shown a right triangle?



Solution


Step 1: Label the sides of the triangle.



Step 2: Calculate the square of the the longest side (one side of the equation a2 + b2 = c2)

The longest side, c, is 11 cm long.

c2 = 112
= 121 cm2

Step 3: Calculate the sum of the squares of the other two sides (one side of the equation a2 + b2 = c2)

The other two sides, a and b, are 6 cm and 7 cm

a2 + b2 = 62 + y2
= 36 + 49
= 85 cm2

This is not a right triangle because 121 cm2 and 85 cm2 are not the same value.

Alternate Solution


You can also do these calculations in one step.

a2 + b2 = c2
62 + 72 = 112
36 + 49 = 121
85 cm2 ≠ 121 cm2

This is not a right triangle because 121 cm2 and 85 cm2 are not the same value.


Now, it is your turn! Complete the questions in your Chapter 3, Lesson 1 Practice Makes Perfect that refer to Determining if a Triangle has a Right Angle.



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