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Finding the Fourth Proportional to 207.81, 311.72 and 70.85

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Solution

The fourth proportional to 207.81, 311.72 and 70.85 is: 106.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.81 : 311.72 = 70.85 : x
  2. Step 2: Convert to fraction form
    207.81/311.72 = 70.85/x
  3. Step 3: Cross multiply
    207.81x = 311.72 × 70.85
  4. Step 4: Simplify right side
    207.81x = 22,085.36
  5. Step 5: Solve for x
    x = 22,085.36/207.81
  6. Step 6: Final answer
    x = 106.28

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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.