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Finding the Fourth Proportional to 80.57, 120.21 and 71.45

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Solution

The fourth proportional to 80.57, 120.21 and 71.45 is: 106.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.57 : 120.21 = 71.45 : x
  2. Step 2: Convert to fraction form
    80.57/120.21 = 71.45/x
  3. Step 3: Cross multiply
    80.57x = 120.21 × 71.45
  4. Step 4: Simplify right side
    80.57x = 8,588.40
  5. Step 5: Solve for x
    x = 8,588.40/80.57
  6. Step 6: Final answer
    x = 106.60

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.