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Finding the Fourth Proportional to 840.72, 1,261.04 and 515.60

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Solution

The fourth proportional to 840.72, 1,261.04 and 515.60 is: 773.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.72 : 1,261.04 = 515.60 : x
  2. Step 2: Convert to fraction form
    840.72/1,261.04 = 515.60/x
  3. Step 3: Cross multiply
    840.72x = 1,261.04 × 515.60
  4. Step 4: Simplify right side
    840.72x = 650,192.22
  5. Step 5: Solve for x
    x = 650,192.22/840.72
  6. Step 6: Final answer
    x = 773.38

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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.