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Finding the Fourth Proportional to 660.31, 990.51 and 221.56

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Solution

The fourth proportional to 660.31, 990.51 and 221.56 is: 332.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.31 : 990.51 = 221.56 : x
  2. Step 2: Convert to fraction form
    660.31/990.51 = 221.56/x
  3. Step 3: Cross multiply
    660.31x = 990.51 × 221.56
  4. Step 4: Simplify right side
    660.31x = 219,454.92
  5. Step 5: Solve for x
    x = 219,454.92/660.31
  6. Step 6: Final answer
    x = 332.35

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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.