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Finding the Fourth Proportional to 875.20, 1,208.51 and 781.78

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Solution

The fourth proportional to 875.20, 1,208.51 and 781.78 is: 1,079.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    875.20 : 1,208.51 = 781.78 : x
  2. Step 2: Convert to fraction form
    875.20/1,208.51 = 781.78/x
  3. Step 3: Cross multiply
    875.20x = 1,208.51 × 781.78
  4. Step 4: Simplify right side
    875.20x = 944,785.04
  5. Step 5: Solve for x
    x = 944,785.04/875.20
  6. Step 6: Final answer
    x = 1,079.51

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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.