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Finding the Fourth Proportional to 85.17, 127.59 and 77.90

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Solution

The fourth proportional to 85.17, 127.59 and 77.90 is: 116.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.17 : 127.59 = 77.90 : x
  2. Step 2: Convert to fraction form
    85.17/127.59 = 77.90/x
  3. Step 3: Cross multiply
    85.17x = 127.59 × 77.90
  4. Step 4: Simplify right side
    85.17x = 9,939.26
  5. Step 5: Solve for x
    x = 9,939.26/85.17
  6. Step 6: Final answer
    x = 116.70

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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.