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Finding the Fourth Proportional to 989.23, 1,485.38 and 945.40

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Solution

The fourth proportional to 989.23, 1,485.38 and 945.40 is: 1,419.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.23 : 1,485.38 = 945.40 : x
  2. Step 2: Convert to fraction form
    989.23/1,485.38 = 945.40/x
  3. Step 3: Cross multiply
    989.23x = 1,485.38 × 945.40
  4. Step 4: Simplify right side
    989.23x = 1,404,278.25
  5. Step 5: Solve for x
    x = 1,404,278.25/989.23
  6. Step 6: Final answer
    x = 1,419.57

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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.