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Finding the Fourth Proportional to 431.73, 645.98 and 386.78

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Solution

The fourth proportional to 431.73, 645.98 and 386.78 is: 578.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.73 : 645.98 = 386.78 : x
  2. Step 2: Convert to fraction form
    431.73/645.98 = 386.78/x
  3. Step 3: Cross multiply
    431.73x = 645.98 × 386.78
  4. Step 4: Simplify right side
    431.73x = 249,846.98
  5. Step 5: Solve for x
    x = 249,846.98/431.73
  6. Step 6: Final answer
    x = 578.71

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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.