What is the length of the radius of a circle with a center at the origin and a point on the circle at 8+15i

The answer is a because i went through all the other ones that it didn’t come out right

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.