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Finding the Fourth Proportional to 1,129.09, 1,557.26 and 686.91

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Solution

The fourth proportional to 1,129.09, 1,557.26 and 686.91 is: 947.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,129.09 : 1,557.26 = 686.91 : x
  2. Step 2: Convert to fraction form
    1,129.09/1,557.26 = 686.91/x
  3. Step 3: Cross multiply
    1,129.09x = 1,557.26 × 686.91
  4. Step 4: Simplify right side
    1,129.09x = 1,069,693.69
  5. Step 5: Solve for x
    x = 1,069,693.69/1,129.09
  6. Step 6: Final answer
    x = 947.39

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.