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Finding the Fourth Proportional to 987.87, 1,362.98 and 688.78

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Solution

The fourth proportional to 987.87, 1,362.98 and 688.78 is: 950.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.87 : 1,362.98 = 688.78 : x
  2. Step 2: Convert to fraction form
    987.87/1,362.98 = 688.78/x
  3. Step 3: Cross multiply
    987.87x = 1,362.98 × 688.78
  4. Step 4: Simplify right side
    987.87x = 938,789.08
  5. Step 5: Solve for x
    x = 938,789.08/987.87
  6. Step 6: Final answer
    x = 950.32

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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.