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Finding the Fourth Proportional to 864.40, 1,290.56 and 855.28

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Solution

The fourth proportional to 864.40, 1,290.56 and 855.28 is: 1,276.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.40 : 1,290.56 = 855.28 : x
  2. Step 2: Convert to fraction form
    864.40/1,290.56 = 855.28/x
  3. Step 3: Cross multiply
    864.40x = 1,290.56 × 855.28
  4. Step 4: Simplify right side
    864.40x = 1,103,790.16
  5. Step 5: Solve for x
    x = 1,103,790.16/864.40
  6. Step 6: Final answer
    x = 1,276.94

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.