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Finding the Fourth Proportional to 1,381.04, 2,071.70 and 640.49

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Solution

The fourth proportional to 1,381.04, 2,071.70 and 640.49 is: 960.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.04 : 2,071.70 = 640.49 : x
  2. Step 2: Convert to fraction form
    1,381.04/2,071.70 = 640.49/x
  3. Step 3: Cross multiply
    1,381.04x = 2,071.70 × 640.49
  4. Step 4: Simplify right side
    1,381.04x = 1,326,889.57
  5. Step 5: Solve for x
    x = 1,326,889.57/1,381.04
  6. Step 6: Final answer
    x = 960.79

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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.