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Finding the Fourth Proportional to 85.20, 117.72 and 63.42

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Solution

The fourth proportional to 85.20, 117.72 and 63.42 is: 87.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.20 : 117.72 = 63.42 : x
  2. Step 2: Convert to fraction form
    85.20/117.72 = 63.42/x
  3. Step 3: Cross multiply
    85.20x = 117.72 × 63.42
  4. Step 4: Simplify right side
    85.20x = 7,465.80
  5. Step 5: Solve for x
    x = 7,465.80/85.20
  6. Step 6: Final answer
    x = 87.63

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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.