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Finding the Fourth Proportional to 7,121.90, 9,828.06 and 3,978.09

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Solution

The fourth proportional to 7,121.90, 9,828.06 and 3,978.09 is: 5,489.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    7,121.90 : 9,828.06 = 3,978.09 : x
  2. Step 2: Convert to fraction form
    7,121.90/9,828.06 = 3,978.09/x
  3. Step 3: Cross multiply
    7,121.90x = 9,828.06 × 3,978.09
  4. Step 4: Simplify right side
    7,121.90x = 39,096,907.21
  5. Step 5: Solve for x
    x = 39,096,907.21/7,121.90
  6. Step 6: Final answer
    x = 5,489.67

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.