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Finding the Fourth Proportional to 712.80, 1,067.98 and 388.40

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Solution

The fourth proportional to 712.80, 1,067.98 and 388.40 is: 581.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.80 : 1,067.98 = 388.40 : x
  2. Step 2: Convert to fraction form
    712.80/1,067.98 = 388.40/x
  3. Step 3: Cross multiply
    712.80x = 1,067.98 × 388.40
  4. Step 4: Simplify right side
    712.80x = 414,803.43
  5. Step 5: Solve for x
    x = 414,803.43/712.80
  6. Step 6: Final answer
    x = 581.94

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.