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Finding the Fourth Proportional to 281.21, 421.43 and 143.91

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Solution

The fourth proportional to 281.21, 421.43 and 143.91 is: 215.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.21 : 421.43 = 143.91 : x
  2. Step 2: Convert to fraction form
    281.21/421.43 = 143.91/x
  3. Step 3: Cross multiply
    281.21x = 421.43 × 143.91
  4. Step 4: Simplify right side
    281.21x = 60,647.99
  5. Step 5: Solve for x
    x = 60,647.99/281.21
  6. Step 6: Final answer
    x = 215.67

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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.