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Finding the Fourth Proportional to 78.09, 116.46 and 66.75

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Solution

The fourth proportional to 78.09, 116.46 and 66.75 is: 99.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.09 : 116.46 = 66.75 : x
  2. Step 2: Convert to fraction form
    78.09/116.46 = 66.75/x
  3. Step 3: Cross multiply
    78.09x = 116.46 × 66.75
  4. Step 4: Simplify right side
    78.09x = 7,773.71
  5. Step 5: Solve for x
    x = 7,773.71/78.09
  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.