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Finding the Fourth Proportional to 85.05, 117.36 and 77.76

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Solution

The fourth proportional to 85.05, 117.36 and 77.76 is: 107.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.05 : 117.36 = 77.76 : x
  2. Step 2: Convert to fraction form
    85.05/117.36 = 77.76/x
  3. Step 3: Cross multiply
    85.05x = 117.36 × 77.76
  4. Step 4: Simplify right side
    85.05x = 9,125.91
  5. Step 5: Solve for x
    x = 9,125.91/85.05
  6. Step 6: Final answer
    x = 107.30

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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.