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Finding the Fourth Proportional to 1,409.68, 2,115.64 and 640.24

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Solution

The fourth proportional to 1,409.68, 2,115.64 and 640.24 is: 960.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,409.68 : 2,115.64 = 640.24 : x
  2. Step 2: Convert to fraction form
    1,409.68/2,115.64 = 640.24/x
  3. Step 3: Cross multiply
    1,409.68x = 2,115.64 × 640.24
  4. Step 4: Simplify right side
    1,409.68x = 1,354,517.35
  5. Step 5: Solve for x
    x = 1,354,517.35/1,409.68
  6. Step 6: Final answer
    x = 960.87

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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.