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Finding the Fourth Proportional to 206.50, 309.84 and 78.34

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Solution

The fourth proportional to 206.50, 309.84 and 78.34 is: 117.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.50 : 309.84 = 78.34 : x
  2. Step 2: Convert to fraction form
    206.50/309.84 = 78.34/x
  3. Step 3: Cross multiply
    206.50x = 309.84 × 78.34
  4. Step 4: Simplify right side
    206.50x = 24,272.87
  5. Step 5: Solve for x
    x = 24,272.87/206.50
  6. Step 6: Final answer
    x = 117.54

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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.