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Finding the Fourth Proportional to 543.90, 814.65 and 421.20

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Solution

The fourth proportional to 543.90, 814.65 and 421.20 is: 630.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    543.90 : 814.65 = 421.20 : x
  2. Step 2: Convert to fraction form
    543.90/814.65 = 421.20/x
  3. Step 3: Cross multiply
    543.90x = 814.65 × 421.20
  4. Step 4: Simplify right side
    543.90x = 343,130.58
  5. Step 5: Solve for x
    x = 343,130.58/543.90
  6. Step 6: Final answer
    x = 630.87

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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.