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Finding the Fourth Proportional to 724.21, 1,085.90 and 261.90

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Solution

The fourth proportional to 724.21, 1,085.90 and 261.90 is: 392.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    724.21 : 1,085.90 = 261.90 : x
  2. Step 2: Convert to fraction form
    724.21/1,085.90 = 261.90/x
  3. Step 3: Cross multiply
    724.21x = 1,085.90 × 261.90
  4. Step 4: Simplify right side
    724.21x = 284,395.90
  5. Step 5: Solve for x
    x = 284,395.90/724.21
  6. Step 6: Final answer
    x = 392.70

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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.