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Finding the Fourth Proportional to 77.76, 117.18 and 71.82

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Solution

The fourth proportional to 77.76, 117.18 and 71.82 is: 108.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.76 : 117.18 = 71.82 : x
  2. Step 2: Convert to fraction form
    77.76/117.18 = 71.82/x
  3. Step 3: Cross multiply
    77.76x = 117.18 × 71.82
  4. Step 4: Simplify right side
    77.76x = 8,415.87
  5. Step 5: Solve for x
    x = 8,415.87/77.76
  6. Step 6: Final answer
    x = 108.23

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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.