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Finding the Fourth Proportional to 51.78, 77.12 and 51.18

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Solution

The fourth proportional to 51.78, 77.12 and 51.18 is: 76.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.78 : 77.12 = 51.18 : x
  2. Step 2: Convert to fraction form
    51.78/77.12 = 51.18/x
  3. Step 3: Cross multiply
    51.78x = 77.12 × 51.18
  4. Step 4: Simplify right side
    51.78x = 3,946.75
  5. Step 5: Solve for x
    x = 3,946.75/51.78
  6. Step 6: Final answer
    x = 76.22

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.