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Finding the Fourth Proportional to 900.80, 1,243.99 and 621.75

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Solution

The fourth proportional to 900.80, 1,243.99 and 621.75 is: 858.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    900.80 : 1,243.99 = 621.75 : x
  2. Step 2: Convert to fraction form
    900.80/1,243.99 = 621.75/x
  3. Step 3: Cross multiply
    900.80x = 1,243.99 × 621.75
  4. Step 4: Simplify right side
    900.80x = 773,456.22
  5. Step 5: Solve for x
    x = 773,456.22/900.80
  6. Step 6: Final answer
    x = 858.63

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.