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Finding the Fourth Proportional to 21,213.60, 31,820.40 and 20,407.20

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Solution

The fourth proportional to 21,213.60, 31,820.40 and 20,407.20 is: 30,610.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,213.60 : 31,820.40 = 20,407.20 : x
  2. Step 2: Convert to fraction form
    21,213.60/31,820.40 = 20,407.20/x
  3. Step 3: Cross multiply
    21,213.60x = 31,820.40 × 20,407.20
  4. Step 4: Simplify right side
    21,213.60x = 649,365,266.88
  5. Step 5: Solve for x
    x = 649,365,266.88/21,213.60
  6. Step 6: Final answer
    x = 30,610.80

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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.