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Finding the Fourth Proportional to 1,287.18, 1,775.75 and 867.80

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Solution

The fourth proportional to 1,287.18, 1,775.75 and 867.80 is: 1,197.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.18 : 1,775.75 = 867.80 : x
  2. Step 2: Convert to fraction form
    1,287.18/1,775.75 = 867.80/x
  3. Step 3: Cross multiply
    1,287.18x = 1,775.75 × 867.80
  4. Step 4: Simplify right side
    1,287.18x = 1,540,995.85
  5. Step 5: Solve for x
    x = 1,540,995.85/1,287.18
  6. Step 6: Final answer
    x = 1,197.19

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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.