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Finding the Fourth Proportional to 723.84, 1,086.20 and 399.40

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Solution

The fourth proportional to 723.84, 1,086.20 and 399.40 is: 599.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    723.84 : 1,086.20 = 399.40 : x
  2. Step 2: Convert to fraction form
    723.84/1,086.20 = 399.40/x
  3. Step 3: Cross multiply
    723.84x = 1,086.20 × 399.40
  4. Step 4: Simplify right side
    723.84x = 433,828.28
  5. Step 5: Solve for x
    x = 433,828.28/723.84
  6. Step 6: Final answer
    x = 599.34

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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.