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Finding the Fourth Proportional to 1,287.84, 1,928.16 and 854.40

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Solution

The fourth proportional to 1,287.84, 1,928.16 and 854.40 is: 1,279.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.84 : 1,928.16 = 854.40 : x
  2. Step 2: Convert to fraction form
    1,287.84/1,928.16 = 854.40/x
  3. Step 3: Cross multiply
    1,287.84x = 1,928.16 × 854.40
  4. Step 4: Simplify right side
    1,287.84x = 1,647,419.90
  5. Step 5: Solve for x
    x = 1,647,419.90/1,287.84
  6. Step 6: Final answer
    x = 1,279.21

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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.