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Finding the Fourth Proportional to 420.08, 628.62 and 257.28

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Solution

The fourth proportional to 420.08, 628.62 and 257.28 is: 385.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.08 : 628.62 = 257.28 : x
  2. Step 2: Convert to fraction form
    420.08/628.62 = 257.28/x
  3. Step 3: Cross multiply
    420.08x = 628.62 × 257.28
  4. Step 4: Simplify right side
    420.08x = 161,731.35
  5. Step 5: Solve for x
    x = 161,731.35/420.08
  6. Step 6: Final answer
    x = 385.00

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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.