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Edexcel IGCSE Maths 復習筆記 4.8.1 Pythagoras Theorem

Category: IGCSE課程, 國際課程, 教材筆記, 福利干貨 Date: 2022年6月28日下午6:45

Edexcel IGCSE Maths 復習筆記 4.8.1 Pythagoras Theorem

What is Pythagoras?

Pythagoras was a Greek mathematician who lived over 2500 years ago
He is most famous for Pythagoras’ Theorem, which includes the important formula for right-angled triangles

Pythagoras' theorem?

The longest side in a right-angled triangle is called the?hypotenuse?– this will always be the side opposite the right angle
If we label the hypotenuse c, and label the other two sides a and b:

Right-Angled-Triangle-abc

then Pythagoras’ Theorem tells us that:

a²?+ b²?= c²

(where a, b, and c are the lengths of the three sides)

Using Pythagoras’ theorem

To find the length of the?hypotenuse?use:c = √a²?+ b²
(Note that when finding the hypotenuse you?add?inside the square root)
To find the length of?one of the other sides?use:
a = √c²?– b²?or b = √c²?– a²Note that when finding one of the other sides you?subtract?inside the square root

Exam Tip

‘Reality check’ your answers.? If the hypotenuse ends up being shorter than another side in your answer, you’ve made a mistake somewhere!If your calculator gives you a ‘Math ERROR’ result, you probably subtracted the wrong way around in the square root.In questions with multiple steps, don’t round off (to 1 decimal place, 3 significant figures, etc) until the very end.