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Finding the Fourth Proportional to 85.20, 117.48 and 69.72

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Solution

The fourth proportional to 85.20, 117.48 and 69.72 is: 96.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.20 : 117.48 = 69.72 : x
  2. Step 2: Convert to fraction form
    85.20/117.48 = 69.72/x
  3. Step 3: Cross multiply
    85.20x = 117.48 × 69.72
  4. Step 4: Simplify right side
    85.20x = 8,190.71
  5. Step 5: Solve for x
    x = 8,190.71/85.20
  6. Step 6: Final answer
    x = 96.14

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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.