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Finding the Fourth Proportional to 122.81, 169.40 and 86.00

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Solution

The fourth proportional to 122.81, 169.40 and 86.00 is: 118.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.81 : 169.40 = 86.00 : x
  2. Step 2: Convert to fraction form
    122.81/169.40 = 86.00/x
  3. Step 3: Cross multiply
    122.81x = 169.40 × 86.00
  4. Step 4: Simplify right side
    122.81x = 14,567.77
  5. Step 5: Solve for x
    x = 14,567.77/122.81
  6. Step 6: Final answer
    x = 118.63

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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.