THE RIGHT-ANGLED TRIANGLE

PYTHAGORAS THEOREM

This is about right angled triangle. A triangle which has one side to be a right angle is said to be right angled triangle.

Figure 3.25

Pythogaras theorem states that for every right angled triangle:
Square on the hypotanous= sum of the squares of the other two sides.
From figure 3.25
|BC|² = |AC|² + |AB|²
From c² =a² + b², we can also write the followin;
a²=c² - b² or a=√(b² - c²)
NOTE: The longer side or the side opposite to the right angle is the hypotanous

Pythogaras' theorem can be used to find the third side of a right-angled triangle if the other two sides are known.
EXAMPLE:
Find x in the figure below

SOLUTION
From Pythogaras theorem, a²=b² + c²
x² = (5cm)² + (3cm)²
x² = 25cm² + 9cm²
x² = 36cm²
√x²= √36cm²
x = 6cm

END OF LESSON EXERCISE 

Solve for the missing sides of the right-angled triangle

1.

2. 

 3.