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Finding the Fourth Proportional to 860.64, 1,289.88 and 427.56

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Solution

The fourth proportional to 860.64, 1,289.88 and 427.56 is: 640.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.64 : 1,289.88 = 427.56 : x
  2. Step 2: Convert to fraction form
    860.64/1,289.88 = 427.56/x
  3. Step 3: Cross multiply
    860.64x = 1,289.88 × 427.56
  4. Step 4: Simplify right side
    860.64x = 551,501.09
  5. Step 5: Solve for x
    x = 551,501.09/860.64
  6. Step 6: Final answer
    x = 640.80

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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.