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Finding the Fourth Proportional to 989.87, 1,365.43 and 653.78

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Solution

The fourth proportional to 989.87, 1,365.43 and 653.78 is: 901.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.87 : 1,365.43 = 653.78 : x
  2. Step 2: Convert to fraction form
    989.87/1,365.43 = 653.78/x
  3. Step 3: Cross multiply
    989.87x = 1,365.43 × 653.78
  4. Step 4: Simplify right side
    989.87x = 892,680.73
  5. Step 5: Solve for x
    x = 892,680.73/989.87
  6. Step 6: Final answer
    x = 901.82

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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.