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Finding the Fourth Proportional to 1,328.71, 1,991.85 and 712.84

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Solution

The fourth proportional to 1,328.71, 1,991.85 and 712.84 is: 1,068.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,328.71 : 1,991.85 = 712.84 : x
  2. Step 2: Convert to fraction form
    1,328.71/1,991.85 = 712.84/x
  3. Step 3: Cross multiply
    1,328.71x = 1,991.85 × 712.84
  4. Step 4: Simplify right side
    1,328.71x = 1,419,870.35
  5. Step 5: Solve for x
    x = 1,419,870.35/1,328.71
  6. Step 6: Final answer
    x = 1,068.61

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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.