What does james need to justify this statement in a proof. because ∠a=90° then ∠a is a right angle. syllogisms symmetric property definition of right angles definition of angle measure

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.