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Finding the Fourth Proportional to 285.68, 429.20 and 212.78

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Solution

The fourth proportional to 285.68, 429.20 and 212.78 is: 319.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.68 : 429.20 = 212.78 : x
  2. Step 2: Convert to fraction form
    285.68/429.20 = 212.78/x
  3. Step 3: Cross multiply
    285.68x = 429.20 × 212.78
  4. Step 4: Simplify right side
    285.68x = 91,323.57
  5. Step 5: Solve for x
    x = 91,323.57/285.68
  6. Step 6: Final answer
    x = 319.67

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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.