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Finding the Fourth Proportional to 85, 117.40 and 68.74

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Solution

The fourth proportional to 85, 117.40 and 68.74 is: 94.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    85 : 117.40 = 68.74 : x
  2. Step 2: Convert to fraction form
    85/117.40 = 68.74/x
  3. Step 3: Cross multiply
    85x = 117.40 × 68.74
  4. Step 4: Simplify right side
    85x = 8,070.08
  5. Step 5: Solve for x
    x = 8,070.08/85
  6. Step 6: Final answer
    x = 94.94

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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.