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Finding the Fourth Proportional to 989.50, 1,365.78 and 657.76

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Solution

The fourth proportional to 989.50, 1,365.78 and 657.76 is: 907.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.50 : 1,365.78 = 657.76 : x
  2. Step 2: Convert to fraction form
    989.50/1,365.78 = 657.76/x
  3. Step 3: Cross multiply
    989.50x = 1,365.78 × 657.76
  4. Step 4: Simplify right side
    989.50x = 898,355.45
  5. Step 5: Solve for x
    x = 898,355.45/989.50
  6. Step 6: Final answer
    x = 907.89

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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.