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Finding the Fourth Proportional to 978.29, 1,352.64 and 855.28

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Solution

The fourth proportional to 978.29, 1,352.64 and 855.28 is: 1,182.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.29 : 1,352.64 = 855.28 : x
  2. Step 2: Convert to fraction form
    978.29/1,352.64 = 855.28/x
  3. Step 3: Cross multiply
    978.29x = 1,352.64 × 855.28
  4. Step 4: Simplify right side
    978.29x = 1,156,885.94
  5. Step 5: Solve for x
    x = 1,156,885.94/978.29
  6. Step 6: Final answer
    x = 1,182.56

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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.