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Finding the Fourth Proportional to 878.28, 1,315.80 and 781.08

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Solution

The fourth proportional to 878.28, 1,315.80 and 781.08 is: 1,170.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.28 : 1,315.80 = 781.08 : x
  2. Step 2: Convert to fraction form
    878.28/1,315.80 = 781.08/x
  3. Step 3: Cross multiply
    878.28x = 1,315.80 × 781.08
  4. Step 4: Simplify right side
    878.28x = 1,027,745.06
  5. Step 5: Solve for x
    x = 1,027,745.06/878.28
  6. Step 6: Final answer
    x = 1,170.18

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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.