Final answer:
To find the value of a when b=4 and they are in direct proportion with the equation a=8b, substitute the value of b into the equation to get a=32.
Step-by-step explanation:
When dealing with proportionality, it is important to recognize the nature of the relationship between the variables in question. In this case, we have a direct proportionality situation where a is directly proportional to b, expressed as a = 8b. This equation means that for any change in b, a will change by eight times that amount.
To solve the mathematical problem completely, we simply need to substitute the given value of b into the proportionality equation. Given that b = 4, we replace b with 4 in the equation, giving us a = 8 × 4. After performing the multiplication, we find that a = 32. This value of a is the required solution when b = 4.
Since the result is an integer and not a decimal, we don't need to round it to one decimal place as the question suggests.