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Finding the Fourth Proportional to 420.12, 628.56 and 275.40

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Solution

The fourth proportional to 420.12, 628.56 and 275.40 is: 412.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.12 : 628.56 = 275.40 : x
  2. Step 2: Convert to fraction form
    420.12/628.56 = 275.40/x
  3. Step 3: Cross multiply
    420.12x = 628.56 × 275.40
  4. Step 4: Simplify right side
    420.12x = 173,105.42
  5. Step 5: Solve for x
    x = 173,105.42/420.12
  6. Step 6: Final answer
    x = 412.04

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.