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Finding the Fourth Proportional to 281.05, 420.90 and 212.20

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Solution

The fourth proportional to 281.05, 420.90 and 212.20 is: 317.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.05 : 420.90 = 212.20 : x
  2. Step 2: Convert to fraction form
    281.05/420.90 = 212.20/x
  3. Step 3: Cross multiply
    281.05x = 420.90 × 212.20
  4. Step 4: Simplify right side
    281.05x = 89,314.98
  5. Step 5: Solve for x
    x = 89,314.98/281.05
  6. Step 6: Final answer
    x = 317.79

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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.