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Finding the Fourth Proportional to 860.14, 1,290.30 and 427.18

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Solution

The fourth proportional to 860.14, 1,290.30 and 427.18 is: 640.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.14 : 1,290.30 = 427.18 : x
  2. Step 2: Convert to fraction form
    860.14/1,290.30 = 427.18/x
  3. Step 3: Cross multiply
    860.14x = 1,290.30 × 427.18
  4. Step 4: Simplify right side
    860.14x = 551,190.35
  5. Step 5: Solve for x
    x = 551,190.35/860.14
  6. Step 6: Final answer
    x = 640.81

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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.