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Finding the Fourth Proportional to 127.49, 191.21 and 78.66

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Solution

The fourth proportional to 127.49, 191.21 and 78.66 is: 117.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.49 : 191.21 = 78.66 : x
  2. Step 2: Convert to fraction form
    127.49/191.21 = 78.66/x
  3. Step 3: Cross multiply
    127.49x = 191.21 × 78.66
  4. Step 4: Simplify right side
    127.49x = 15,040.19
  5. Step 5: Solve for x
    x = 15,040.19/127.49
  6. Step 6: Final answer
    x = 117.98

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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.