Determining which side
I can identify which side length is missing and use the appropriate form of Pythagoras' theorem to calculate it.
Determining which side
I can identify which side length is missing and use the appropriate form of Pythagoras' theorem to calculate it.
Lesson details
Key learning points
- The hypotenuse is the side opposite the right angle.
- It does not matter which of the shorter sides is identified as a or b.
Common misconception
I can only use Pythagoras' theorem to find the length of a side of a right-angled triangle when the right-angle marker is labelled, so I know which side is the hypotenuse.
The right-angle marker doesn't need to be explicitly labelled in order to be able to identify the right-angle. You can use knowledge of "interior angles in a triangle sum to 180°" to find the right angle, given two other angles.
Keywords
Right-angled triangle - A right-angled triangle has exactly one 90° interior angle.
Hypotenuse - A hypotenuse is the side of the right-angle triangle which is opposite the right-angle.
Pythagoras’ theorem - Pythagoras’ theorem shows that the sum of the squares of the two shorter sides of a right-angled triangle is equal to the square of its longest side (the hypotenuse).
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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