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Finding the Fourth Proportional to 879.09, 1,320 and 840.14

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Solution

The fourth proportional to 879.09, 1,320 and 840.14 is: 1,261.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.09 : 1,320 = 840.14 : x
  2. Step 2: Convert to fraction form
    879.09/1,320 = 840.14/x
  3. Step 3: Cross multiply
    879.09x = 1,320 × 840.14
  4. Step 4: Simplify right side
    879.09x = 1,108,984.80
  5. Step 5: Solve for x
    x = 1,108,984.80/879.09
  6. Step 6: Final answer
    x = 1,261.51

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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.