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Finding the Fourth Proportional to 128.30, 177.11 and 90.98

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Solution

The fourth proportional to 128.30, 177.11 and 90.98 is: 125.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.30 : 177.11 = 90.98 : x
  2. Step 2: Convert to fraction form
    128.30/177.11 = 90.98/x
  3. Step 3: Cross multiply
    128.30x = 177.11 × 90.98
  4. Step 4: Simplify right side
    128.30x = 16,113.47
  5. Step 5: Solve for x
    x = 16,113.47/128.30
  6. Step 6: Final answer
    x = 125.59

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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.