Home / 8,121.20-12,181.80-7,991.60

Finding the Fourth Proportional to 8,121.20, 12,181.80 and 7,991.60

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Solution

The fourth proportional to 8,121.20, 12,181.80 and 7,991.60 is: 11,987.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,121.20 : 12,181.80 = 7,991.60 : x
  2. Step 2: Convert to fraction form
    8,121.20/12,181.80 = 7,991.60/x
  3. Step 3: Cross multiply
    8,121.20x = 12,181.80 × 7,991.60
  4. Step 4: Simplify right side
    8,121.20x = 97,352,072.88
  5. Step 5: Solve for x
    x = 97,352,072.88/8,121.20
  6. Step 6: Final answer
    x = 11,987.40

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1.5x scale

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.