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Finding the Fourth Proportional to 660.65, 911.45 and 398.57

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Solution

The fourth proportional to 660.65, 911.45 and 398.57 is: 549.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.65 : 911.45 = 398.57 : x
  2. Step 2: Convert to fraction form
    660.65/911.45 = 398.57/x
  3. Step 3: Cross multiply
    660.65x = 911.45 × 398.57
  4. Step 4: Simplify right side
    660.65x = 363,273.07
  5. Step 5: Solve for x
    x = 363,273.07/660.65
  6. Step 6: Final answer
    x = 549.88

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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.