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Finding the Fourth Proportional to 989.80, 1,485.60 and 503.18

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Solution

The fourth proportional to 989.80, 1,485.60 and 503.18 is: 755.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.80 : 1,485.60 = 503.18 : x
  2. Step 2: Convert to fraction form
    989.80/1,485.60 = 503.18/x
  3. Step 3: Cross multiply
    989.80x = 1,485.60 × 503.18
  4. Step 4: Simplify right side
    989.80x = 747,524.21
  5. Step 5: Solve for x
    x = 747,524.21/989.80
  6. Step 6: Final answer
    x = 755.23

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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.