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Finding the Fourth Proportional to 85.42, 127.22 and 80.74

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Solution

The fourth proportional to 85.42, 127.22 and 80.74 is: 120.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.42 : 127.22 = 80.74 : x
  2. Step 2: Convert to fraction form
    85.42/127.22 = 80.74/x
  3. Step 3: Cross multiply
    85.42x = 127.22 × 80.74
  4. Step 4: Simplify right side
    85.42x = 10,271.74
  5. Step 5: Solve for x
    x = 10,271.74/85.42
  6. Step 6: Final answer
    x = 120.25

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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.