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Finding the Fourth Proportional to 420.20, 629.90 and 189.08

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Solution

The fourth proportional to 420.20, 629.90 and 189.08 is: 283.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.20 : 629.90 = 189.08 : x
  2. Step 2: Convert to fraction form
    420.20/629.90 = 189.08/x
  3. Step 3: Cross multiply
    420.20x = 629.90 × 189.08
  4. Step 4: Simplify right side
    420.20x = 119,101.49
  5. Step 5: Solve for x
    x = 119,101.49/420.20
  6. Step 6: Final answer
    x = 283.44

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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.