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Finding the Fourth Proportional to 420.76, 631.04 and 386.88

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Solution

The fourth proportional to 420.76, 631.04 and 386.88 is: 580.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.76 : 631.04 = 386.88 : x
  2. Step 2: Convert to fraction form
    420.76/631.04 = 386.88/x
  3. Step 3: Cross multiply
    420.76x = 631.04 × 386.88
  4. Step 4: Simplify right side
    420.76x = 244,136.76
  5. Step 5: Solve for x
    x = 244,136.76/420.76
  6. Step 6: Final answer
    x = 580.23

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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.