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Finding the Fourth Proportional to 393.96, 543.65 and 221.30

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Solution

The fourth proportional to 393.96, 543.65 and 221.30 is: 305.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.96 : 543.65 = 221.30 : x
  2. Step 2: Convert to fraction form
    393.96/543.65 = 221.30/x
  3. Step 3: Cross multiply
    393.96x = 543.65 × 221.30
  4. Step 4: Simplify right side
    393.96x = 120,307.96
  5. Step 5: Solve for x
    x = 120,307.96/393.96
  6. Step 6: Final answer
    x = 305.38

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.