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Finding the Fourth Proportional to 860.69, 1,290.88 and 392.05

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Solution

The fourth proportional to 860.69, 1,290.88 and 392.05 is: 588.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.69 : 1,290.88 = 392.05 : x
  2. Step 2: Convert to fraction form
    860.69/1,290.88 = 392.05/x
  3. Step 3: Cross multiply
    860.69x = 1,290.88 × 392.05
  4. Step 4: Simplify right side
    860.69x = 506,087.54
  5. Step 5: Solve for x
    x = 506,087.54/860.69
  6. Step 6: Final answer
    x = 588.01

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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.