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Finding the Fourth Proportional to 128.26, 176.86 and 89.38

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Solution

The fourth proportional to 128.26, 176.86 and 89.38 is: 123.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.26 : 176.86 = 89.38 : x
  2. Step 2: Convert to fraction form
    128.26/176.86 = 89.38/x
  3. Step 3: Cross multiply
    128.26x = 176.86 × 89.38
  4. Step 4: Simplify right side
    128.26x = 15,807.75
  5. Step 5: Solve for x
    x = 15,807.75/128.26
  6. Step 6: Final answer
    x = 123.25

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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.