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Finding the Fourth Proportional to 85.77, 129.25 and 77.22

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Solution

The fourth proportional to 85.77, 129.25 and 77.22 is: 116.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.77 : 129.25 = 77.22 : x
  2. Step 2: Convert to fraction form
    85.77/129.25 = 77.22/x
  3. Step 3: Cross multiply
    85.77x = 129.25 × 77.22
  4. Step 4: Simplify right side
    85.77x = 9,980.04
  5. Step 5: Solve for x
    x = 9,980.04/85.77
  6. Step 6: Final answer
    x = 116.36

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.