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Finding the Fourth Proportional to 77.28, 106.72 and 65.12

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Solution

The fourth proportional to 77.28, 106.72 and 65.12 is: 89.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.28 : 106.72 = 65.12 : x
  2. Step 2: Convert to fraction form
    77.28/106.72 = 65.12/x
  3. Step 3: Cross multiply
    77.28x = 106.72 × 65.12
  4. Step 4: Simplify right side
    77.28x = 6,949.61
  5. Step 5: Solve for x
    x = 6,949.61/77.28
  6. Step 6: Final answer
    x = 89.93

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.