An angle is a right angle if and only if it measures 90. write a definition based on the biconditional. a.a right angle measures  .b. if an angle is a right angle, then it measures  .c. an angle is a right angle. d.an angle measures  .

A would be the correct answer kid

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.