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Finding the Fourth Proportional to 228.49, 315.32 and 128.90

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Solution

The fourth proportional to 228.49, 315.32 and 128.90 is: 177.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    228.49 : 315.32 = 128.90 : x
  2. Step 2: Convert to fraction form
    228.49/315.32 = 128.90/x
  3. Step 3: Cross multiply
    228.49x = 315.32 × 128.90
  4. Step 4: Simplify right side
    228.49x = 40,644.75
  5. Step 5: Solve for x
    x = 40,644.75/228.49
  6. Step 6: Final answer
    x = 177.88

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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.