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Finding the Fourth Proportional to 85.67, 128.19 and 51.46

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Solution

The fourth proportional to 85.67, 128.19 and 51.46 is: 77.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.67 : 128.19 = 51.46 : x
  2. Step 2: Convert to fraction form
    85.67/128.19 = 51.46/x
  3. Step 3: Cross multiply
    85.67x = 128.19 × 51.46
  4. Step 4: Simplify right side
    85.67x = 6,596.66
  5. Step 5: Solve for x
    x = 6,596.66/85.67
  6. Step 6: Final answer
    x = 77.00

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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.