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Finding the Fourth Proportional to 991.38, 1,487.70 and 443.91

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Solution

The fourth proportional to 991.38, 1,487.70 and 443.91 is: 666.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.38 : 1,487.70 = 443.91 : x
  2. Step 2: Convert to fraction form
    991.38/1,487.70 = 443.91/x
  3. Step 3: Cross multiply
    991.38x = 1,487.70 × 443.91
  4. Step 4: Simplify right side
    991.38x = 660,404.91
  5. Step 5: Solve for x
    x = 660,404.91/991.38
  6. Step 6: Final answer
    x = 666.15

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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.