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Finding the Fourth Proportional to 89.19, 122.88 and 78.25

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Solution

The fourth proportional to 89.19, 122.88 and 78.25 is: 107.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.19 : 122.88 = 78.25 : x
  2. Step 2: Convert to fraction form
    89.19/122.88 = 78.25/x
  3. Step 3: Cross multiply
    89.19x = 122.88 × 78.25
  4. Step 4: Simplify right side
    89.19x = 9,615.36
  5. Step 5: Solve for x
    x = 9,615.36/89.19
  6. Step 6: Final answer
    x = 107.81

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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.