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Finding the Fourth Proportional to 1,404.64, 1,938.40 and 815.20

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Solution

The fourth proportional to 1,404.64, 1,938.40 and 815.20 is: 1,124.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,404.64 : 1,938.40 = 815.20 : x
  2. Step 2: Convert to fraction form
    1,404.64/1,938.40 = 815.20/x
  3. Step 3: Cross multiply
    1,404.64x = 1,938.40 × 815.20
  4. Step 4: Simplify right side
    1,404.64x = 1,580,183.68
  5. Step 5: Solve for x
    x = 1,580,183.68/1,404.64
  6. Step 6: Final answer
    x = 1,124.97

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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.