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Finding the Fourth Proportional to 136.24, 204.40 and 78.40

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Solution

The fourth proportional to 136.24, 204.40 and 78.40 is: 117.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.24 : 204.40 = 78.40 : x
  2. Step 2: Convert to fraction form
    136.24/204.40 = 78.40/x
  3. Step 3: Cross multiply
    136.24x = 204.40 × 78.40
  4. Step 4: Simplify right side
    136.24x = 16,024.96
  5. Step 5: Solve for x
    x = 16,024.96/136.24
  6. Step 6: Final answer
    x = 117.62

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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.