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Finding the Fourth Proportional to 280.11, 420.17 and 85.11

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Solution

The fourth proportional to 280.11, 420.17 and 85.11 is: 127.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.11 : 420.17 = 85.11 : x
  2. Step 2: Convert to fraction form
    280.11/420.17 = 85.11/x
  3. Step 3: Cross multiply
    280.11x = 420.17 × 85.11
  4. Step 4: Simplify right side
    280.11x = 35,760.88
  5. Step 5: Solve for x
    x = 35,760.88/280.11
  6. Step 6: Final answer
    x = 127.67

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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.