1. **Problem:** Find the lowest common denominator (LCD) of the fractions $\frac{3}{4}$ and $\frac{3}{16}$. 2. **Formula and rules:** The LCD is the least common multiple (LCM) of the denominators. To find the LCM, factor each denominator into primes and take the highest powers of each prime. 3. **Step-by-step:** - Denominators: 4 and 16 - Prime factorization: $4 = 2^2$, $16 = 2^4$ - LCM takes the highest power of 2, which is $2^4 = 16$ 4. **Answer:** The lowest common denominator is $16$.