Since this is clearly homework...
Hint: what does angle do? (atan2 would also suffice, but then you would need to know how to extract the real and imaginary parts of the number.)
Next, what does abs do, when applied to a complex number? Again, you could do this using more prosaic calls, as applied to the real and imaginary parts of the number. Or, you could play with what happens when you multiply a number with its conjugate transpose, then taking a sqrt.
Hey, this is homework. You need to do the thinking. That is why god (or more likely, your instructor) gave you the homework assignment, not me.