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Finding the Fourth Proportional to 420.72, 631.32 and 388.08

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Solution

The fourth proportional to 420.72, 631.32 and 388.08 is: 582.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.72 : 631.32 = 388.08 : x
  2. Step 2: Convert to fraction form
    420.72/631.32 = 388.08/x
  3. Step 3: Cross multiply
    420.72x = 631.32 × 388.08
  4. Step 4: Simplify right side
    420.72x = 245,002.67
  5. Step 5: Solve for x
    x = 245,002.67/420.72
  6. Step 6: Final answer
    x = 582.34

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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.