Cross-multiply to see if the ratio forms a pro forms a proportion and No if it does not. (10)/(15)=(5)/(8)

To determine if the given ratio forms a proportion, we need to cross-multiply and check if the products are equal.<br /><br />Cross-multiplying the given ratio:<br />$\frac{10}{15} = \frac{5}{8}$<br /><br />$10 \times 8 = 80$<br />$15 \times 5 = 75$<br /><br />Since the products are not equal, the given ratio does not form a proportion.