Home / 20,921.76-28,861.65-12,420

Finding the Fourth Proportional to 20,921.76, 28,861.65 and 12,420

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Solution

The fourth proportional to 20,921.76, 28,861.65 and 12,420 is: 17,133.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,921.76 : 28,861.65 = 12,420 : x
  2. Step 2: Convert to fraction form
    20,921.76/28,861.65 = 12,420/x
  3. Step 3: Cross multiply
    20,921.76x = 28,861.65 × 12,420
  4. Step 4: Simplify right side
    20,921.76x = 358,461,693
  5. Step 5: Solve for x
    x = 358,461,693/20,921.76
  6. Step 6: Final answer
    x = 17,133.44

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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.