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Finding the Fourth Proportional to 938.40, 1,407.89 and 665.02

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Solution

The fourth proportional to 938.40, 1,407.89 and 665.02 is: 997.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.40 : 1,407.89 = 665.02 : x
  2. Step 2: Convert to fraction form
    938.40/1,407.89 = 665.02/x
  3. Step 3: Cross multiply
    938.40x = 1,407.89 × 665.02
  4. Step 4: Simplify right side
    938.40x = 936,271.68
  5. Step 5: Solve for x
    x = 936,271.68/938.40
  6. Step 6: Final answer
    x = 997.73

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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.