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Finding the Fourth Proportional to 1,319.20, 1,978.83 and 345.40

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Solution

The fourth proportional to 1,319.20, 1,978.83 and 345.40 is: 518.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.20 : 1,978.83 = 345.40 : x
  2. Step 2: Convert to fraction form
    1,319.20/1,978.83 = 345.40/x
  3. Step 3: Cross multiply
    1,319.20x = 1,978.83 × 345.40
  4. Step 4: Simplify right side
    1,319.20x = 683,487.88
  5. Step 5: Solve for x
    x = 683,487.88/1,319.20
  6. Step 6: Final answer
    x = 518.11

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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.