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Finding the Fourth Proportional to 1,078.21, 1,618.80 and 858.97

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Solution

The fourth proportional to 1,078.21, 1,618.80 and 858.97 is: 1,289.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.21 : 1,618.80 = 858.97 : x
  2. Step 2: Convert to fraction form
    1,078.21/1,618.80 = 858.97/x
  3. Step 3: Cross multiply
    1,078.21x = 1,618.80 × 858.97
  4. Step 4: Simplify right side
    1,078.21x = 1,390,500.64
  5. Step 5: Solve for x
    x = 1,390,500.64/1,078.21
  6. Step 6: Final answer
    x = 1,289.64

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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.