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Finding the Fourth Proportional to 840.79, 1,261.34 and 688.10

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Solution

The fourth proportional to 840.79, 1,261.34 and 688.10 is: 1,032.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.79 : 1,261.34 = 688.10 : x
  2. Step 2: Convert to fraction form
    840.79/1,261.34 = 688.10/x
  3. Step 3: Cross multiply
    840.79x = 1,261.34 × 688.10
  4. Step 4: Simplify right side
    840.79x = 867,924.61
  5. Step 5: Solve for x
    x = 867,924.61/840.79
  6. Step 6: Final answer
    x = 1,032.28

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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.