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Finding the Fourth Proportional to 74.88, 102.78 and 68.40

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Solution

The fourth proportional to 74.88, 102.78 and 68.40 is: 93.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.88 : 102.78 = 68.40 : x
  2. Step 2: Convert to fraction form
    74.88/102.78 = 68.40/x
  3. Step 3: Cross multiply
    74.88x = 102.78 × 68.40
  4. Step 4: Simplify right side
    74.88x = 7,030.15
  5. Step 5: Solve for x
    x = 7,030.15/74.88
  6. Step 6: Final answer
    x = 93.89

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.