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Finding the Fourth Proportional to 678.90, 1,011.74 and 605.80

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Solution

The fourth proportional to 678.90, 1,011.74 and 605.80 is: 902.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.90 : 1,011.74 = 605.80 : x
  2. Step 2: Convert to fraction form
    678.90/1,011.74 = 605.80/x
  3. Step 3: Cross multiply
    678.90x = 1,011.74 × 605.80
  4. Step 4: Simplify right side
    678.90x = 612,912.09
  5. Step 5: Solve for x
    x = 612,912.09/678.90
  6. Step 6: Final answer
    x = 902.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.