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Finding the Fourth Proportional to 840.24, 1,259.90 and 312.92

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Solution

The fourth proportional to 840.24, 1,259.90 and 312.92 is: 469.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.24 : 1,259.90 = 312.92 : x
  2. Step 2: Convert to fraction form
    840.24/1,259.90 = 312.92/x
  3. Step 3: Cross multiply
    840.24x = 1,259.90 × 312.92
  4. Step 4: Simplify right side
    840.24x = 394,247.91
  5. Step 5: Solve for x
    x = 394,247.91/840.24
  6. Step 6: Final answer
    x = 469.21

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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.