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Finding the Fourth Proportional to 810.54, 1,215.81 and 400.55

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Solution

The fourth proportional to 810.54, 1,215.81 and 400.55 is: 600.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.54 : 1,215.81 = 400.55 : x
  2. Step 2: Convert to fraction form
    810.54/1,215.81 = 400.55/x
  3. Step 3: Cross multiply
    810.54x = 1,215.81 × 400.55
  4. Step 4: Simplify right side
    810.54x = 486,986.62
  5. Step 5: Solve for x
    x = 486,986.62/810.54
  6. Step 6: Final answer
    x = 600.82

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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.