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Finding the Fourth Proportional to 860.81, 1,291.01 and 398.15

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Solution

The fourth proportional to 860.81, 1,291.01 and 398.15 is: 597.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.81 : 1,291.01 = 398.15 : x
  2. Step 2: Convert to fraction form
    860.81/1,291.01 = 398.15/x
  3. Step 3: Cross multiply
    860.81x = 1,291.01 × 398.15
  4. Step 4: Simplify right side
    860.81x = 514,007.19
  5. Step 5: Solve for x
    x = 514,007.19/860.81
  6. Step 6: Final answer
    x = 597.12

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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.