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Finding the Fourth Proportional to 390.78, 586.44 and 147.30

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Solution

The fourth proportional to 390.78, 586.44 and 147.30 is: 221.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 586.44 = 147.30 : x
  2. Step 2: Convert to fraction form
    390.78/586.44 = 147.30/x
  3. Step 3: Cross multiply
    390.78x = 586.44 × 147.30
  4. Step 4: Simplify right side
    390.78x = 86,382.61
  5. Step 5: Solve for x
    x = 86,382.61/390.78
  6. Step 6: Final answer
    x = 221.05

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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.