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Finding the Fourth Proportional to 128.92, 177.96 and 90.14

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Solution

The fourth proportional to 128.92, 177.96 and 90.14 is: 124.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.92 : 177.96 = 90.14 : x
  2. Step 2: Convert to fraction form
    128.92/177.96 = 90.14/x
  3. Step 3: Cross multiply
    128.92x = 177.96 × 90.14
  4. Step 4: Simplify right side
    128.92x = 16,041.31
  5. Step 5: Solve for x
    x = 16,041.31/128.92
  6. Step 6: Final answer
    x = 124.43

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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.