If 20% of N equals 90, find the value of N.

Introduction / Context:
Recovering a whole from a known part and its percentage is a staple calculation. Converting 20% to decimal 0.20 allows direct division to obtain N.

Given Data / Assumptions:

• 0.20 * N = 90.

Concept / Approach:
Divide the known part by the decimal percentage: N = 90 / 0.20. Alternatively, since 20% is one-fifth, multiply by 5 to get N directly without decimals.

Step-by-Step Solution:

Verification / Alternative check:
20% of 450 = 0.20 * 450 = 90, confirming correctness.

Why Other Options Are Wrong:

• 350, 250, 550: Do not satisfy 20% equals 90 when tested.

Common Pitfalls:
Dividing 90 by 20 (getting 4.5) rather than by 0.20, or misreading 20% as 0.002.

Final Answer: