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Finding the Fourth Proportional to 810.52, 1,214.87 and 421.11

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Solution

The fourth proportional to 810.52, 1,214.87 and 421.11 is: 631.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.52 : 1,214.87 = 421.11 : x
  2. Step 2: Convert to fraction form
    810.52/1,214.87 = 421.11/x
  3. Step 3: Cross multiply
    810.52x = 1,214.87 × 421.11
  4. Step 4: Simplify right side
    810.52x = 511,591.80
  5. Step 5: Solve for x
    x = 511,591.80/810.52
  6. Step 6: Final answer
    x = 631.19

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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.