Consider the complex number $z = 3 - 4i$. The modulus of a complex number $a + bi$ is given by the formula $$ |z| = ext{sqrt}(a^2 + b^2) $$ where $a$ is the real part and $b$ is the imaginary part. You are asked to find the modulus of the complex number $z$.
After calculating the modulus, you are to express your answer as a decimal rounded to two decimal places. Provide your answer as a grid-in response.