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Finding the Fourth Proportional to 20,128.40, 30,181.80 and 8,428.40

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Solution

The fourth proportional to 20,128.40, 30,181.80 and 8,428.40 is: 12,638.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,128.40 : 30,181.80 = 8,428.40 : x
  2. Step 2: Convert to fraction form
    20,128.40/30,181.80 = 8,428.40/x
  3. Step 3: Cross multiply
    20,128.40x = 30,181.80 × 8,428.40
  4. Step 4: Simplify right side
    20,128.40x = 254,384,283.12
  5. Step 5: Solve for x
    x = 254,384,283.12/20,128.40
  6. Step 6: Final answer
    x = 12,638.08

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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.