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Finding the Fourth Proportional to 78.13, 116.61 and 67.81

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Solution

The fourth proportional to 78.13, 116.61 and 67.81 is: 101.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.13 : 116.61 = 67.81 : x
  2. Step 2: Convert to fraction form
    78.13/116.61 = 67.81/x
  3. Step 3: Cross multiply
    78.13x = 116.61 × 67.81
  4. Step 4: Simplify right side
    78.13x = 7,907.32
  5. Step 5: Solve for x
    x = 7,907.32/78.13
  6. Step 6: Final answer
    x = 101.21

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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.