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Finding the Fourth Proportional to 85.80, 118.14 and 77.70

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Solution

The fourth proportional to 85.80, 118.14 and 77.70 is: 106.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.80 : 118.14 = 77.70 : x
  2. Step 2: Convert to fraction form
    85.80/118.14 = 77.70/x
  3. Step 3: Cross multiply
    85.80x = 118.14 × 77.70
  4. Step 4: Simplify right side
    85.80x = 9,180.07
  5. Step 5: Solve for x
    x = 9,180.07/85.80
  6. Step 6: Final answer
    x = 106.99

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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.