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Finding the Fourth Proportional to 840.72, 1,259.70 and 515.16

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Solution

The fourth proportional to 840.72, 1,259.70 and 515.16 is: 771.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.72 : 1,259.70 = 515.16 : x
  2. Step 2: Convert to fraction form
    840.72/1,259.70 = 515.16/x
  3. Step 3: Cross multiply
    840.72x = 1,259.70 × 515.16
  4. Step 4: Simplify right side
    840.72x = 648,947.05
  5. Step 5: Solve for x
    x = 648,947.05/840.72
  6. Step 6: Final answer
    x = 771.89

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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.