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Finding the Fourth Proportional to 128.56, 177.28 and 112.16

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Solution

The fourth proportional to 128.56, 177.28 and 112.16 is: 154.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.56 : 177.28 = 112.16 : x
  2. Step 2: Convert to fraction form
    128.56/177.28 = 112.16/x
  3. Step 3: Cross multiply
    128.56x = 177.28 × 112.16
  4. Step 4: Simplify right side
    128.56x = 19,883.72
  5. Step 5: Solve for x
    x = 19,883.72/128.56
  6. Step 6: Final answer
    x = 154.66

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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.