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Finding the Fourth Proportional to 1,380.70, 2,071.56 and 640.67

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Solution

The fourth proportional to 1,380.70, 2,071.56 and 640.67 is: 961.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.70 : 2,071.56 = 640.67 : x
  2. Step 2: Convert to fraction form
    1,380.70/2,071.56 = 640.67/x
  3. Step 3: Cross multiply
    1,380.70x = 2,071.56 × 640.67
  4. Step 4: Simplify right side
    1,380.70x = 1,327,186.35
  5. Step 5: Solve for x
    x = 1,327,186.35/1,380.70
  6. Step 6: Final answer
    x = 961.24

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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.