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Finding the Fourth Proportional to 990, 1,365.12 and 723.24

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Solution

The fourth proportional to 990, 1,365.12 and 723.24 is: 997.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    990 : 1,365.12 = 723.24 : x
  2. Step 2: Convert to fraction form
    990/1,365.12 = 723.24/x
  3. Step 3: Cross multiply
    990x = 1,365.12 × 723.24
  4. Step 4: Simplify right side
    990x = 987,309.39
  5. Step 5: Solve for x
    x = 987,309.39/990
  6. Step 6: Final answer
    x = 997.28

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.