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Finding the Fourth Proportional to 89.76, 135.24 and 77.88

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Solution

The fourth proportional to 89.76, 135.24 and 77.88 is: 117.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.76 : 135.24 = 77.88 : x
  2. Step 2: Convert to fraction form
    89.76/135.24 = 77.88/x
  3. Step 3: Cross multiply
    89.76x = 135.24 × 77.88
  4. Step 4: Simplify right side
    89.76x = 10,532.49
  5. Step 5: Solve for x
    x = 10,532.49/89.76
  6. Step 6: Final answer
    x = 117.34

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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.