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Finding the Fourth Proportional to 127.12, 190.90 and 78.47

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Solution

The fourth proportional to 127.12, 190.90 and 78.47 is: 117.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.12 : 190.90 = 78.47 : x
  2. Step 2: Convert to fraction form
    127.12/190.90 = 78.47/x
  3. Step 3: Cross multiply
    127.12x = 190.90 × 78.47
  4. Step 4: Simplify right side
    127.12x = 14,979.92
  5. Step 5: Solve for x
    x = 14,979.92/127.12
  6. Step 6: Final answer
    x = 117.84

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.