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Finding the Fourth Proportional to 128.48, 190.10 and 128.12

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Solution

The fourth proportional to 128.48, 190.10 and 128.12 is: 189.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.48 : 190.10 = 128.12 : x
  2. Step 2: Convert to fraction form
    128.48/190.10 = 128.12/x
  3. Step 3: Cross multiply
    128.48x = 190.10 × 128.12
  4. Step 4: Simplify right side
    128.48x = 24,355.61
  5. Step 5: Solve for x
    x = 24,355.61/128.48
  6. Step 6: Final answer
    x = 189.57

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Why These Related Problems?

These problems maintain the same ratio (1.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.