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Finding the Fourth Proportional to 1,272.70, 1,906.16 and 686.68

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Solution

The fourth proportional to 1,272.70, 1,906.16 and 686.68 is: 1,028.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,272.70 : 1,906.16 = 686.68 : x
  2. Step 2: Convert to fraction form
    1,272.70/1,906.16 = 686.68/x
  3. Step 3: Cross multiply
    1,272.70x = 1,906.16 × 686.68
  4. Step 4: Simplify right side
    1,272.70x = 1,308,921.95
  5. Step 5: Solve for x
    x = 1,308,921.95/1,272.70
  6. Step 6: Final answer
    x = 1,028.46

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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.