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Finding the Fourth Proportional to 938.31, 1,407.78 and 418.67

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Solution

The fourth proportional to 938.31, 1,407.78 and 418.67 is: 628.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.31 : 1,407.78 = 418.67 : x
  2. Step 2: Convert to fraction form
    938.31/1,407.78 = 418.67/x
  3. Step 3: Cross multiply
    938.31x = 1,407.78 × 418.67
  4. Step 4: Simplify right side
    938.31x = 589,395.25
  5. Step 5: Solve for x
    x = 589,395.25/938.31
  6. Step 6: Final answer
    x = 628.15

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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.