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Finding the Fourth Proportional to 68.76, 94.90 and 42.90

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Solution

The fourth proportional to 68.76, 94.90 and 42.90 is: 59.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.76 : 94.90 = 42.90 : x
  2. Step 2: Convert to fraction form
    68.76/94.90 = 42.90/x
  3. Step 3: Cross multiply
    68.76x = 94.90 × 42.90
  4. Step 4: Simplify right side
    68.76x = 4,071.21
  5. Step 5: Solve for x
    x = 4,071.21/68.76
  6. Step 6: Final answer
    x = 59.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.