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Finding the Fourth Proportional to 390.86, 538.89 and 250.72

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Solution

The fourth proportional to 390.86, 538.89 and 250.72 is: 345.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.86 : 538.89 = 250.72 : x
  2. Step 2: Convert to fraction form
    390.86/538.89 = 250.72/x
  3. Step 3: Cross multiply
    390.86x = 538.89 × 250.72
  4. Step 4: Simplify right side
    390.86x = 135,109.25
  5. Step 5: Solve for x
    x = 135,109.25/390.86
  6. Step 6: Final answer
    x = 345.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.