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Finding the Fourth Proportional to 390.57, 586.40 and 251.95

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Solution

The fourth proportional to 390.57, 586.40 and 251.95 is: 378.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.57 : 586.40 = 251.95 : x
  2. Step 2: Convert to fraction form
    390.57/586.40 = 251.95/x
  3. Step 3: Cross multiply
    390.57x = 586.40 × 251.95
  4. Step 4: Simplify right side
    390.57x = 147,744.92
  5. Step 5: Solve for x
    x = 147,744.92/390.57
  6. Step 6: Final answer
    x = 378.28

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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.