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Finding the Fourth Proportional to 763.18, 1,143.55 and 438.78

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Solution

The fourth proportional to 763.18, 1,143.55 and 438.78 is: 657.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    763.18 : 1,143.55 = 438.78 : x
  2. Step 2: Convert to fraction form
    763.18/1,143.55 = 438.78/x
  3. Step 3: Cross multiply
    763.18x = 1,143.55 × 438.78
  4. Step 4: Simplify right side
    763.18x = 501,766.87
  5. Step 5: Solve for x
    x = 501,766.87/763.18
  6. Step 6: Final answer
    x = 657.47

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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.