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Finding the Fourth Proportional to 840.85, 1,259.91 and 515.53

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Solution

The fourth proportional to 840.85, 1,259.91 and 515.53 is: 772.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.85 : 1,259.91 = 515.53 : x
  2. Step 2: Convert to fraction form
    840.85/1,259.91 = 515.53/x
  3. Step 3: Cross multiply
    840.85x = 1,259.91 × 515.53
  4. Step 4: Simplify right side
    840.85x = 649,521.40
  5. Step 5: Solve for x
    x = 649,521.40/840.85
  6. Step 6: Final answer
    x = 772.46

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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.