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Finding the Fourth Proportional to 989.80, 1,485.30 and 557.26

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Solution

The fourth proportional to 989.80, 1,485.30 and 557.26 is: 836.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.80 : 1,485.30 = 557.26 : x
  2. Step 2: Convert to fraction form
    989.80/1,485.30 = 557.26/x
  3. Step 3: Cross multiply
    989.80x = 1,485.30 × 557.26
  4. Step 4: Simplify right side
    989.80x = 827,698.28
  5. Step 5: Solve for x
    x = 827,698.28/989.80
  6. Step 6: Final answer
    x = 836.23

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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.