1. The problem asks to identify which ratios are equivalent to $11:16$. 2. Two ratios $a:b$ and $c:d$ are equivalent if their cross products are equal, i.e., $a \times d = b \times c$. 3. Check each given ratio: - For $55:80$: $$11 \times 80 = 880$$ $$16 \times 55 = 880$$ Since $880 = 880$, $55:80$ is equivalent to $11:16$. - For $8:64$: $$11 \times 64 = 704$$ $$16 \times 8 = 128$$ Since $704 \neq 128$, $8:64$ is not equivalent to $11:16$. - For $7:24$: $$11 \times 24 = 264$$ $$16 \times 7 = 112$$ Since $264 \neq 112$, $7:24$ is not equivalent to $11:16$. 4. Therefore, the only ratio equivalent to $11:16$ is $55:80$.