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Finding the Fourth Proportional to 810.42, 1,213.80 and 485.10

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Solution

The fourth proportional to 810.42, 1,213.80 and 485.10 is: 726.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.42 : 1,213.80 = 485.10 : x
  2. Step 2: Convert to fraction form
    810.42/1,213.80 = 485.10/x
  3. Step 3: Cross multiply
    810.42x = 1,213.80 × 485.10
  4. Step 4: Simplify right side
    810.42x = 588,814.38
  5. Step 5: Solve for x
    x = 588,814.38/810.42
  6. Step 6: Final answer
    x = 726.55

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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.