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Finding the Fourth Proportional to 1,372.21, 1,893.32 and 812.78

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Solution

The fourth proportional to 1,372.21, 1,893.32 and 812.78 is: 1,121.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,372.21 : 1,893.32 = 812.78 : x
  2. Step 2: Convert to fraction form
    1,372.21/1,893.32 = 812.78/x
  3. Step 3: Cross multiply
    1,372.21x = 1,893.32 × 812.78
  4. Step 4: Simplify right side
    1,372.21x = 1,538,864.47
  5. Step 5: Solve for x
    x = 1,538,864.47/1,372.21
  6. Step 6: Final answer
    x = 1,121.45

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1.5x scale

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.