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Finding the Fourth Proportional to 78.81, 118.28 and 75.84

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Solution

The fourth proportional to 78.81, 118.28 and 75.84 is: 113.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.81 : 118.28 = 75.84 : x
  2. Step 2: Convert to fraction form
    78.81/118.28 = 75.84/x
  3. Step 3: Cross multiply
    78.81x = 118.28 × 75.84
  4. Step 4: Simplify right side
    78.81x = 8,970.36
  5. Step 5: Solve for x
    x = 8,970.36/78.81
  6. Step 6: Final answer
    x = 113.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.