Area of a triangle = height x base ÷ 2
When ever you have an isosceles triangle, remember that you can split it in half to form two right angled triangles - which allow you to use Pythagoras' Theorem.
So we split 10cm in half to get 5cm.
We can then use 13cm and 5cm to work out the height:
Height = √(13² - 5²) (Note: you subtract because you are using the
= √144 (hypotenuse)
= 12
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Now to get the area, we just multiply the base (which is 10) by the height (which is 12) and divide by 2:
Area = 12 x 10 ÷ 2
= 6 x 10 (note: 12 ÷ 2 = 6 )
= 60 cm²
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Answer:
60 cm²
