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Finding the Fourth Proportional to 387.69, 581.30 and 140.78

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Solution

The fourth proportional to 387.69, 581.30 and 140.78 is: 211.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.69 : 581.30 = 140.78 : x
  2. Step 2: Convert to fraction form
    387.69/581.30 = 140.78/x
  3. Step 3: Cross multiply
    387.69x = 581.30 × 140.78
  4. Step 4: Simplify right side
    387.69x = 81,832.51
  5. Step 5: Solve for x
    x = 81,832.51/387.69
  6. Step 6: Final answer
    x = 211.08

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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.