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Finding the Fourth Proportional to 280.12, 386.10 and 221.80

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Solution

The fourth proportional to 280.12, 386.10 and 221.80 is: 305.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.12 : 386.10 = 221.80 : x
  2. Step 2: Convert to fraction form
    280.12/386.10 = 221.80/x
  3. Step 3: Cross multiply
    280.12x = 386.10 × 221.80
  4. Step 4: Simplify right side
    280.12x = 85,636.98
  5. Step 5: Solve for x
    x = 85,636.98/280.12
  6. Step 6: Final answer
    x = 305.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.