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Finding the Fourth Proportional to 390.98, 586.46 and 147.40

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Solution

The fourth proportional to 390.98, 586.46 and 147.40 is: 221.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.98 : 586.46 = 147.40 : x
  2. Step 2: Convert to fraction form
    390.98/586.46 = 147.40/x
  3. Step 3: Cross multiply
    390.98x = 586.46 × 147.40
  4. Step 4: Simplify right side
    390.98x = 86,444.20
  5. Step 5: Solve for x
    x = 86,444.20/390.98
  6. Step 6: Final answer
    x = 221.10

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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.