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Finding the Fourth Proportional to 726.40, 1,089.60 and 611.20

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Solution

The fourth proportional to 726.40, 1,089.60 and 611.20 is: 916.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    726.40 : 1,089.60 = 611.20 : x
  2. Step 2: Convert to fraction form
    726.40/1,089.60 = 611.20/x
  3. Step 3: Cross multiply
    726.40x = 1,089.60 × 611.20
  4. Step 4: Simplify right side
    726.40x = 665,963.52
  5. Step 5: Solve for x
    x = 665,963.52/726.40
  6. Step 6: Final answer
    x = 916.80

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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.