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Finding the Fourth Proportional to 208.79, 313.17 and 86.99

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Solution

The fourth proportional to 208.79, 313.17 and 86.99 is: 130.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.79 : 313.17 = 86.99 : x
  2. Step 2: Convert to fraction form
    208.79/313.17 = 86.99/x
  3. Step 3: Cross multiply
    208.79x = 313.17 × 86.99
  4. Step 4: Simplify right side
    208.79x = 27,242.53
  5. Step 5: Solve for x
    x = 27,242.53/208.79
  6. Step 6: Final answer
    x = 130.48

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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.