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Finding the Fourth Proportional to 438.23, 656.78 and 206.61

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Solution

The fourth proportional to 438.23, 656.78 and 206.61 is: 309.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.23 : 656.78 = 206.61 : x
  2. Step 2: Convert to fraction form
    438.23/656.78 = 206.61/x
  3. Step 3: Cross multiply
    438.23x = 656.78 × 206.61
  4. Step 4: Simplify right side
    438.23x = 135,696.28
  5. Step 5: Solve for x
    x = 135,696.28/438.23
  6. Step 6: Final answer
    x = 309.65

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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.