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Finding the Fourth Proportional to 866.40, 1,299.60 and 858.30

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Solution

The fourth proportional to 866.40, 1,299.60 and 858.30 is: 1,287.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.40 : 1,299.60 = 858.30 : x
  2. Step 2: Convert to fraction form
    866.40/1,299.60 = 858.30/x
  3. Step 3: Cross multiply
    866.40x = 1,299.60 × 858.30
  4. Step 4: Simplify right side
    866.40x = 1,115,446.68
  5. Step 5: Solve for x
    x = 1,115,446.68/866.40
  6. Step 6: Final answer
    x = 1,287.45

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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.