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Finding the Fourth Proportional to 987.15, 1,479.31 and 725.09

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Solution

The fourth proportional to 987.15, 1,479.31 and 725.09 is: 1,086.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.15 : 1,479.31 = 725.09 : x
  2. Step 2: Convert to fraction form
    987.15/1,479.31 = 725.09/x
  3. Step 3: Cross multiply
    987.15x = 1,479.31 × 725.09
  4. Step 4: Simplify right side
    987.15x = 1,072,637.49
  5. Step 5: Solve for x
    x = 1,072,637.49/987.15
  6. Step 6: Final answer
    x = 1,086.60

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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.