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Finding the Fourth Proportional to 420.68, 630.20 and 318.08

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Solution

The fourth proportional to 420.68, 630.20 and 318.08 is: 476.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.68 : 630.20 = 318.08 : x
  2. Step 2: Convert to fraction form
    420.68/630.20 = 318.08/x
  3. Step 3: Cross multiply
    420.68x = 630.20 × 318.08
  4. Step 4: Simplify right side
    420.68x = 200,454.02
  5. Step 5: Solve for x
    x = 200,454.02/420.68
  6. Step 6: Final answer
    x = 476.50

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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.