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Finding the Fourth Proportional to 78.94, 117.75 and 67.40

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Solution

The fourth proportional to 78.94, 117.75 and 67.40 is: 100.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.94 : 117.75 = 67.40 : x
  2. Step 2: Convert to fraction form
    78.94/117.75 = 67.40/x
  3. Step 3: Cross multiply
    78.94x = 117.75 × 67.40
  4. Step 4: Simplify right side
    78.94x = 7,936.35
  5. Step 5: Solve for x
    x = 7,936.35/78.94
  6. Step 6: Final answer
    x = 100.54

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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.