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Finding the Fourth Proportional to 420.54, 630.78 and 189.42

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Solution

The fourth proportional to 420.54, 630.78 and 189.42 is: 284.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.54 : 630.78 = 189.42 : x
  2. Step 2: Convert to fraction form
    420.54/630.78 = 189.42/x
  3. Step 3: Cross multiply
    420.54x = 630.78 × 189.42
  4. Step 4: Simplify right side
    420.54x = 119,482.35
  5. Step 5: Solve for x
    x = 119,482.35/420.54
  6. Step 6: Final answer
    x = 284.12

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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.