The problem visible in the image seems to involve a proportion or sequence:

32 : 21 = 28 : ?

This is a common ratio or proportion problem. To solve for the missing value, we can use the cross-multiplication method:

$\text{Let the missing value be } x.$

$32 : 21 = 28 : x \implies \frac{32}{21} = \frac{28}{x}.$

Solving for $x$:

Cross-multiply: $32x = 21 \cdot 28$

$32x = 588$

Divide both sides by 32: $x = \frac{588}{32} = 18.375$

Final Answer:

The missing value is 18.375.

Would you like further clarification or detailed steps?

Related Questions:

1. What is a ratio, and how is it applied in mathematics?
2. How does cross-multiplication work for solving proportions?
3. Can this type of problem involve whole-number solutions only?
4. What are some real-world applications of ratios?
5. How does simplifying fractions relate to solving proportions?

Tip:

When solving ratio problems, ensure that the units or contexts of the terms are consistent to avoid errors.