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Finding the Fourth Proportional to 68.58, 102.78 and 39.70

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Solution

The fourth proportional to 68.58, 102.78 and 39.70 is: 59.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.58 : 102.78 = 39.70 : x
  2. Step 2: Convert to fraction form
    68.58/102.78 = 39.70/x
  3. Step 3: Cross multiply
    68.58x = 102.78 × 39.70
  4. Step 4: Simplify right side
    68.58x = 4,080.37
  5. Step 5: Solve for x
    x = 4,080.37/68.58
  6. Step 6: Final answer
    x = 59.50

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.