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Finding the Fourth Proportional to 208.67, 312.79 and 100.40

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Solution

The fourth proportional to 208.67, 312.79 and 100.40 is: 150.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.67 : 312.79 = 100.40 : x
  2. Step 2: Convert to fraction form
    208.67/312.79 = 100.40/x
  3. Step 3: Cross multiply
    208.67x = 312.79 × 100.40
  4. Step 4: Simplify right side
    208.67x = 31,404.12
  5. Step 5: Solve for x
    x = 31,404.12/208.67
  6. Step 6: Final answer
    x = 150.50

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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.