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Finding the Fourth Proportional to 989.63, 1,485.18 and 768.89

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Solution

The fourth proportional to 989.63, 1,485.18 and 768.89 is: 1,153.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.63 : 1,485.18 = 768.89 : x
  2. Step 2: Convert to fraction form
    989.63/1,485.18 = 768.89/x
  3. Step 3: Cross multiply
    989.63x = 1,485.18 × 768.89
  4. Step 4: Simplify right side
    989.63x = 1,141,940.05
  5. Step 5: Solve for x
    x = 1,141,940.05/989.63
  6. Step 6: Final answer
    x = 1,153.91

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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.