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Finding the Fourth Proportional to 89.76, 134.70 and 71.80

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Solution

The fourth proportional to 89.76, 134.70 and 71.80 is: 107.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.76 : 134.70 = 71.80 : x
  2. Step 2: Convert to fraction form
    89.76/134.70 = 71.80/x
  3. Step 3: Cross multiply
    89.76x = 134.70 × 71.80
  4. Step 4: Simplify right side
    89.76x = 9,671.46
  5. Step 5: Solve for x
    x = 9,671.46/89.76
  6. Step 6: Final answer
    x = 107.75

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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.