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Finding the Fourth Proportional to 280.78, 386.63 and 231.57

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Solution

The fourth proportional to 280.78, 386.63 and 231.57 is: 318.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.78 : 386.63 = 231.57 : x
  2. Step 2: Convert to fraction form
    280.78/386.63 = 231.57/x
  3. Step 3: Cross multiply
    280.78x = 386.63 × 231.57
  4. Step 4: Simplify right side
    280.78x = 89,531.91
  5. Step 5: Solve for x
    x = 89,531.91/280.78
  6. Step 6: Final answer
    x = 318.87

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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.