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Finding the Fourth Proportional to 127.10, 191.34 and 86.78

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Solution

The fourth proportional to 127.10, 191.34 and 86.78 is: 130.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.10 : 191.34 = 86.78 : x
  2. Step 2: Convert to fraction form
    127.10/191.34 = 86.78/x
  3. Step 3: Cross multiply
    127.10x = 191.34 × 86.78
  4. Step 4: Simplify right side
    127.10x = 16,603.53
  5. Step 5: Solve for x
    x = 16,603.53/127.10
  6. Step 6: Final answer
    x = 130.64

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.