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Finding the Fourth Proportional to 1,978, 2,730.16 and 1,138.80

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Solution

The fourth proportional to 1,978, 2,730.16 and 1,138.80 is: 1,571.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,978 : 2,730.16 = 1,138.80 : x
  2. Step 2: Convert to fraction form
    1,978/2,730.16 = 1,138.80/x
  3. Step 3: Cross multiply
    1,978x = 2,730.16 × 1,138.80
  4. Step 4: Simplify right side
    1,978x = 3,109,106.21
  5. Step 5: Solve for x
    x = 3,109,106.21/1,978
  6. Step 6: Final answer
    x = 1,571.84

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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.