Step-by-step explanation:
Let
c = 11.5 cm
a = 8.9 cm
b = ?
Since this is a right triangle, we can use Pythagorean theorem to find the length of side b:
[tex]c^2 = a^2 + b^2[/tex]
[tex]\Rightarrow b^2 = c^2 - a^2[/tex]
Taking the square root of the equation above, we get
[tex]b = \sqrt{c^2 - a^2} = \sqrt{(11.5\:\text{cm})^2 - (8.9\:\text{cm})^2}[/tex]
[tex]\:\:\:\:=7.3\:\text{cm}[/tex]