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Finding the Fourth Proportional to 206.26, 309.40 and 78

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Solution

The fourth proportional to 206.26, 309.40 and 78 is: 117.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.26 : 309.40 = 78 : x
  2. Step 2: Convert to fraction form
    206.26/309.40 = 78/x
  3. Step 3: Cross multiply
    206.26x = 309.40 × 78
  4. Step 4: Simplify right side
    206.26x = 24,133.20
  5. Step 5: Solve for x
    x = 24,133.20/206.26
  6. Step 6: Final answer
    x = 117.00

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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.