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Finding the Fourth Proportional to 724.48, 1,087.38 and 399.40

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Solution

The fourth proportional to 724.48, 1,087.38 and 399.40 is: 599.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    724.48 : 1,087.38 = 399.40 : x
  2. Step 2: Convert to fraction form
    724.48/1,087.38 = 399.40/x
  3. Step 3: Cross multiply
    724.48x = 1,087.38 × 399.40
  4. Step 4: Simplify right side
    724.48x = 434,299.57
  5. Step 5: Solve for x
    x = 434,299.57/724.48
  6. Step 6: Final answer
    x = 599.46

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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.