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Finding the Fourth Proportional to 390.90, 586.29 and 147.42

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Solution

The fourth proportional to 390.90, 586.29 and 147.42 is: 221.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.90 : 586.29 = 147.42 : x
  2. Step 2: Convert to fraction form
    390.90/586.29 = 147.42/x
  3. Step 3: Cross multiply
    390.90x = 586.29 × 147.42
  4. Step 4: Simplify right side
    390.90x = 86,430.87
  5. Step 5: Solve for x
    x = 86,430.87/390.90
  6. Step 6: Final answer
    x = 221.11

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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.