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Finding the Fourth Proportional to 987.27, 1,479.72 and 438.27

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Solution

The fourth proportional to 987.27, 1,479.72 and 438.27 is: 656.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.27 : 1,479.72 = 438.27 : x
  2. Step 2: Convert to fraction form
    987.27/1,479.72 = 438.27/x
  3. Step 3: Cross multiply
    987.27x = 1,479.72 × 438.27
  4. Step 4: Simplify right side
    987.27x = 648,516.88
  5. Step 5: Solve for x
    x = 648,516.88/987.27
  6. Step 6: Final answer
    x = 656.88

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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.