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Finding the Fourth Proportional to 987.53, 1,481.81 and 640.76

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Solution

The fourth proportional to 987.53, 1,481.81 and 640.76 is: 961.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.53 : 1,481.81 = 640.76 : x
  2. Step 2: Convert to fraction form
    987.53/1,481.81 = 640.76/x
  3. Step 3: Cross multiply
    987.53x = 1,481.81 × 640.76
  4. Step 4: Simplify right side
    987.53x = 949,473.96
  5. Step 5: Solve for x
    x = 949,473.96/987.53
  6. Step 6: Final answer
    x = 961.47

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.