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Finding the Fourth Proportional to 840.12, 1,259.99 and 319.94

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Solution

The fourth proportional to 840.12, 1,259.99 and 319.94 is: 479.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.12 : 1,259.99 = 319.94 : x
  2. Step 2: Convert to fraction form
    840.12/1,259.99 = 319.94/x
  3. Step 3: Cross multiply
    840.12x = 1,259.99 × 319.94
  4. Step 4: Simplify right side
    840.12x = 403,113.30
  5. Step 5: Solve for x
    x = 403,113.30/840.12
  6. Step 6: Final answer
    x = 479.83

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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.