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Finding the Fourth Proportional to 705.28, 1,058.40 and 320.80

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Solution

The fourth proportional to 705.28, 1,058.40 and 320.80 is: 481.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    705.28 : 1,058.40 = 320.80 : x
  2. Step 2: Convert to fraction form
    705.28/1,058.40 = 320.80/x
  3. Step 3: Cross multiply
    705.28x = 1,058.40 × 320.80
  4. Step 4: Simplify right side
    705.28x = 339,534.72
  5. Step 5: Solve for x
    x = 339,534.72/705.28
  6. Step 6: Final answer
    x = 481.42

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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.