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Finding the Fourth Proportional to 78.25, 116.82 and 66.91

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Solution

The fourth proportional to 78.25, 116.82 and 66.91 is: 99.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.25 : 116.82 = 66.91 : x
  2. Step 2: Convert to fraction form
    78.25/116.82 = 66.91/x
  3. Step 3: Cross multiply
    78.25x = 116.82 × 66.91
  4. Step 4: Simplify right side
    78.25x = 7,816.43
  5. Step 5: Solve for x
    x = 7,816.43/78.25
  6. Step 6: Final answer
    x = 99.89

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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.