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Finding the Fourth Proportional to 70, 105 and 68

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Solution

The fourth proportional to 70, 105 and 68 is: 102

Step by Step Solution

  1. Step 1: Write the proportion equation
    70 : 105 = 68 : x
  2. Step 2: Convert to fraction form
    70/105 = 68/x
  3. Step 3: Cross multiply
    70x = 105 × 68
  4. Step 4: Simplify right side
    70x = 7,140
  5. Step 5: Solve for x
    x = 7,140/70
  6. Step 6: Final answer
    x = 102

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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.