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Finding the Fourth Proportional to 85.86, 129.48 and 83.12

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Solution

The fourth proportional to 85.86, 129.48 and 83.12 is: 125.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.86 : 129.48 = 83.12 : x
  2. Step 2: Convert to fraction form
    85.86/129.48 = 83.12/x
  3. Step 3: Cross multiply
    85.86x = 129.48 × 83.12
  4. Step 4: Simplify right side
    85.86x = 10,762.38
  5. Step 5: Solve for x
    x = 10,762.38/85.86
  6. Step 6: Final answer
    x = 125.35

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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.