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Finding the Fourth Proportional to 130.56, 180.21 and 78.81

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Solution

The fourth proportional to 130.56, 180.21 and 78.81 is: 108.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.56 : 180.21 = 78.81 : x
  2. Step 2: Convert to fraction form
    130.56/180.21 = 78.81/x
  3. Step 3: Cross multiply
    130.56x = 180.21 × 78.81
  4. Step 4: Simplify right side
    130.56x = 14,202.35
  5. Step 5: Solve for x
    x = 14,202.35/130.56
  6. Step 6: Final answer
    x = 108.78

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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.