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Finding the Fourth Proportional to 418.80, 628.30 and 213.40

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Solution

The fourth proportional to 418.80, 628.30 and 213.40 is: 320.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    418.80 : 628.30 = 213.40 : x
  2. Step 2: Convert to fraction form
    418.80/628.30 = 213.40/x
  3. Step 3: Cross multiply
    418.80x = 628.30 × 213.40
  4. Step 4: Simplify right side
    418.80x = 134,079.22
  5. Step 5: Solve for x
    x = 134,079.22/418.80
  6. Step 6: Final answer
    x = 320.15

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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.