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Finding the Fourth Proportional to 128.12, 176.76 and 91.34

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Solution

The fourth proportional to 128.12, 176.76 and 91.34 is: 126.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.12 : 176.76 = 91.34 : x
  2. Step 2: Convert to fraction form
    128.12/176.76 = 91.34/x
  3. Step 3: Cross multiply
    128.12x = 176.76 × 91.34
  4. Step 4: Simplify right side
    128.12x = 16,145.26
  5. Step 5: Solve for x
    x = 16,145.26/128.12
  6. Step 6: Final answer
    x = 126.02

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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.