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Finding the Fourth Proportional to 840.21, 1,254.65 and 686.44

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Solution

The fourth proportional to 840.21, 1,254.65 and 686.44 is: 1,025.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.21 : 1,254.65 = 686.44 : x
  2. Step 2: Convert to fraction form
    840.21/1,254.65 = 686.44/x
  3. Step 3: Cross multiply
    840.21x = 1,254.65 × 686.44
  4. Step 4: Simplify right side
    840.21x = 861,241.95
  5. Step 5: Solve for x
    x = 861,241.95/840.21
  6. Step 6: Final answer
    x = 1,025.03

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.