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Finding the Fourth Proportional to 1,009.91, 1,393.31 and 660.80

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Solution

The fourth proportional to 1,009.91, 1,393.31 and 660.80 is: 911.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,009.91 : 1,393.31 = 660.80 : x
  2. Step 2: Convert to fraction form
    1,009.91/1,393.31 = 660.80/x
  3. Step 3: Cross multiply
    1,009.91x = 1,393.31 × 660.80
  4. Step 4: Simplify right side
    1,009.91x = 920,693.93
  5. Step 5: Solve for x
    x = 920,693.93/1,009.91
  6. Step 6: Final answer
    x = 911.66

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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.