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Finding the Fourth Proportional to 21,816, 30,105 and 13,308.30

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Solution

The fourth proportional to 21,816, 30,105 and 13,308.30 is: 18,364.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,816 : 30,105 = 13,308.30 : x
  2. Step 2: Convert to fraction form
    21,816/30,105 = 13,308.30/x
  3. Step 3: Cross multiply
    21,816x = 30,105 × 13,308.30
  4. Step 4: Simplify right side
    21,816x = 400,646,371.50
  5. Step 5: Solve for x
    x = 400,646,371.50/21,816
  6. Step 6: Final answer
    x = 18,364.80

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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.