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Finding the Fourth Proportional to 514.40, 771.90 and 189.78

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Solution

The fourth proportional to 514.40, 771.90 and 189.78 is: 284.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    514.40 : 771.90 = 189.78 : x
  2. Step 2: Convert to fraction form
    514.40/771.90 = 189.78/x
  3. Step 3: Cross multiply
    514.40x = 771.90 × 189.78
  4. Step 4: Simplify right side
    514.40x = 146,491.18
  5. Step 5: Solve for x
    x = 146,491.18/514.40
  6. Step 6: Final answer
    x = 284.78

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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.