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Finding the Fourth Proportional to 85.65, 117.96 and 63.78

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Solution

The fourth proportional to 85.65, 117.96 and 63.78 is: 87.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.65 : 117.96 = 63.78 : x
  2. Step 2: Convert to fraction form
    85.65/117.96 = 63.78/x
  3. Step 3: Cross multiply
    85.65x = 117.96 × 63.78
  4. Step 4: Simplify right side
    85.65x = 7,523.49
  5. Step 5: Solve for x
    x = 7,523.49/85.65
  6. Step 6: Final answer
    x = 87.84

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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.