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Finding the Fourth Proportional to 77.96, 117.45 and 71.28

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Solution

The fourth proportional to 77.96, 117.45 and 71.28 is: 107.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.96 : 117.45 = 71.28 : x
  2. Step 2: Convert to fraction form
    77.96/117.45 = 71.28/x
  3. Step 3: Cross multiply
    77.96x = 117.45 × 71.28
  4. Step 4: Simplify right side
    77.96x = 8,371.84
  5. Step 5: Solve for x
    x = 8,371.84/77.96
  6. Step 6: Final answer
    x = 107.38

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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.