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Finding the Fourth Proportional to 989.64, 1,365.96 and 616.40

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Solution

The fourth proportional to 989.64, 1,365.96 and 616.40 is: 850.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.64 : 1,365.96 = 616.40 : x
  2. Step 2: Convert to fraction form
    989.64/1,365.96 = 616.40/x
  3. Step 3: Cross multiply
    989.64x = 1,365.96 × 616.40
  4. Step 4: Simplify right side
    989.64x = 841,977.74
  5. Step 5: Solve for x
    x = 841,977.74/989.64
  6. Step 6: Final answer
    x = 850.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.