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Finding the Fourth Proportional to 1,380, 1,904.40 and 828

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Solution

The fourth proportional to 1,380, 1,904.40 and 828 is: 1,142.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380 : 1,904.40 = 828 : x
  2. Step 2: Convert to fraction form
    1,380/1,904.40 = 828/x
  3. Step 3: Cross multiply
    1,380x = 1,904.40 × 828
  4. Step 4: Simplify right side
    1,380x = 1,576,843.20
  5. Step 5: Solve for x
    x = 1,576,843.20/1,380
  6. Step 6: Final answer
    x = 1,142.64

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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.