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Finding the Fourth Proportional to 860.38, 1,289.78 and 340.72

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Solution

The fourth proportional to 860.38, 1,289.78 and 340.72 is: 510.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.38 : 1,289.78 = 340.72 : x
  2. Step 2: Convert to fraction form
    860.38/1,289.78 = 340.72/x
  3. Step 3: Cross multiply
    860.38x = 1,289.78 × 340.72
  4. Step 4: Simplify right side
    860.38x = 439,453.84
  5. Step 5: Solve for x
    x = 439,453.84/860.38
  6. Step 6: Final answer
    x = 510.77

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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.