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Finding the Fourth Proportional to 724.80, 1,087.12 and 211.80

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Solution

The fourth proportional to 724.80, 1,087.12 and 211.80 is: 317.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    724.80 : 1,087.12 = 211.80 : x
  2. Step 2: Convert to fraction form
    724.80/1,087.12 = 211.80/x
  3. Step 3: Cross multiply
    724.80x = 1,087.12 × 211.80
  4. Step 4: Simplify right side
    724.80x = 230,252.02
  5. Step 5: Solve for x
    x = 230,252.02/724.80
  6. Step 6: Final answer
    x = 317.68

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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.