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Finding the Fourth Proportional to 70.49, 105.71 and 47.80

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Solution

The fourth proportional to 70.49, 105.71 and 47.80 is: 71.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.49 : 105.71 = 47.80 : x
  2. Step 2: Convert to fraction form
    70.49/105.71 = 47.80/x
  3. Step 3: Cross multiply
    70.49x = 105.71 × 47.80
  4. Step 4: Simplify right side
    70.49x = 5,052.94
  5. Step 5: Solve for x
    x = 5,052.94/70.49
  6. Step 6: Final answer
    x = 71.69

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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.