The given fractions are equivalent to 15/45 because they can be simplified to the same value. When we simplify 3/15, we divide both the numerator and denominator by 3, resulting in 1/5. Similarly, when we simplify 30/90, we divide both the numerator and denominator by 30, resulting in 1/3. When we simplify 3/9, we divide both the numerator and denominator by 3, resulting in 1/3. Lastly, when we simplify 150/450, we divide both the numerator and denominator by 150, resulting in 1/3.