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Finding the Fourth Proportional to 390.65, 538.71 and 250.75

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Solution

The fourth proportional to 390.65, 538.71 and 250.75 is: 345.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.65 : 538.71 = 250.75 : x
  2. Step 2: Convert to fraction form
    390.65/538.71 = 250.75/x
  3. Step 3: Cross multiply
    390.65x = 538.71 × 250.75
  4. Step 4: Simplify right side
    390.65x = 135,078.84
  5. Step 5: Solve for x
    x = 135,078.84/390.65
  6. Step 6: Final answer
    x = 345.78

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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.