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Finding the Fourth Proportional to 860.97, 1,290.42 and 398.12

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Solution

The fourth proportional to 860.97, 1,290.42 and 398.12 is: 596.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.97 : 1,290.42 = 398.12 : x
  2. Step 2: Convert to fraction form
    860.97/1,290.42 = 398.12/x
  3. Step 3: Cross multiply
    860.97x = 1,290.42 × 398.12
  4. Step 4: Simplify right side
    860.97x = 513,742.01
  5. Step 5: Solve for x
    x = 513,742.01/860.97
  6. Step 6: Final answer
    x = 596.70

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Double scale
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1.5x scale

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.