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Finding the Fourth Proportional to 85.16, 127.72 and 78.48

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Solution

The fourth proportional to 85.16, 127.72 and 78.48 is: 117.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.16 : 127.72 = 78.48 : x
  2. Step 2: Convert to fraction form
    85.16/127.72 = 78.48/x
  3. Step 3: Cross multiply
    85.16x = 127.72 × 78.48
  4. Step 4: Simplify right side
    85.16x = 10,023.47
  5. Step 5: Solve for x
    x = 10,023.47/85.16
  6. Step 6: Final answer
    x = 117.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.