Answer:
see explanation
Step-by-step explanation:
Using Pythagoras' identity on the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
AC² = AB² + BC² , substitute values
AC² = 9² + 12² = 81 + 144 = 225 ( take the square root of both sides )
AC = [tex]\sqrt{225}[/tex] = 15 cm
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The area of Δ ABC is calculated as
A = [tex]\frac{1}{2}[/tex] × BC × AB = [tex]\frac{1}{2}[/tex] × 12 × 9 = 6 × 9 = 54 cm²
