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Finding the Fourth Proportional to 136.79, 188.75 and 78.56

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Solution

The fourth proportional to 136.79, 188.75 and 78.56 is: 108.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.79 : 188.75 = 78.56 : x
  2. Step 2: Convert to fraction form
    136.79/188.75 = 78.56/x
  3. Step 3: Cross multiply
    136.79x = 188.75 × 78.56
  4. Step 4: Simplify right side
    136.79x = 14,828.87
  5. Step 5: Solve for x
    x = 14,828.87/136.79
  6. Step 6: Final answer
    x = 108.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.