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Finding the Fourth Proportional to 78.05, 116.56 and 66.66

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Solution

The fourth proportional to 78.05, 116.56 and 66.66 is: 99.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.05 : 116.56 = 66.66 : x
  2. Step 2: Convert to fraction form
    78.05/116.56 = 66.66/x
  3. Step 3: Cross multiply
    78.05x = 116.56 × 66.66
  4. Step 4: Simplify right side
    78.05x = 7,769.89
  5. Step 5: Solve for x
    x = 7,769.89/78.05
  6. Step 6: Final answer
    x = 99.55

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.