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Finding the Fourth Proportional to 810.89, 1,215.49 and 426.41

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Solution

The fourth proportional to 810.89, 1,215.49 and 426.41 is: 639.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.89 : 1,215.49 = 426.41 : x
  2. Step 2: Convert to fraction form
    810.89/1,215.49 = 426.41/x
  3. Step 3: Cross multiply
    810.89x = 1,215.49 × 426.41
  4. Step 4: Simplify right side
    810.89x = 518,297.09
  5. Step 5: Solve for x
    x = 518,297.09/810.89
  6. Step 6: Final answer
    x = 639.17

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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.