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Finding the Fourth Proportional to 1,372.20, 1,892.86 and 812.40

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Solution

The fourth proportional to 1,372.20, 1,892.86 and 812.40 is: 1,120.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,372.20 : 1,892.86 = 812.40 : x
  2. Step 2: Convert to fraction form
    1,372.20/1,892.86 = 812.40/x
  3. Step 3: Cross multiply
    1,372.20x = 1,892.86 × 812.40
  4. Step 4: Simplify right side
    1,372.20x = 1,537,759.46
  5. Step 5: Solve for x
    x = 1,537,759.46/1,372.20
  6. Step 6: Final answer
    x = 1,120.65

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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.