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Finding the Fourth Proportional to 85.78, 117.61 and 85.69

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Solution

The fourth proportional to 85.78, 117.61 and 85.69 is: 117.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.78 : 117.61 = 85.69 : x
  2. Step 2: Convert to fraction form
    85.78/117.61 = 85.69/x
  3. Step 3: Cross multiply
    85.78x = 117.61 × 85.69
  4. Step 4: Simplify right side
    85.78x = 10,078.00
  5. Step 5: Solve for x
    x = 10,078.00/85.78
  6. Step 6: Final answer
    x = 117.49

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.