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Finding the Fourth Proportional to 989.57, 1,485.22 and 771.59

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Solution

The fourth proportional to 989.57, 1,485.22 and 771.59 is: 1,158.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.57 : 1,485.22 = 771.59 : x
  2. Step 2: Convert to fraction form
    989.57/1,485.22 = 771.59/x
  3. Step 3: Cross multiply
    989.57x = 1,485.22 × 771.59
  4. Step 4: Simplify right side
    989.57x = 1,145,973.47
  5. Step 5: Solve for x
    x = 1,145,973.47/989.57
  6. Step 6: Final answer
    x = 1,158.06

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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.