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Finding the Fourth Proportional to 208.07, 311.95 and 86.16

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Solution

The fourth proportional to 208.07, 311.95 and 86.16 is: 129.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.07 : 311.95 = 86.16 : x
  2. Step 2: Convert to fraction form
    208.07/311.95 = 86.16/x
  3. Step 3: Cross multiply
    208.07x = 311.95 × 86.16
  4. Step 4: Simplify right side
    208.07x = 26,878.89
  5. Step 5: Solve for x
    x = 26,878.89/208.07
  6. Step 6: Final answer
    x = 129.18

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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.