Home / 1,286.09-1,929.20-420.38

Finding the Fourth Proportional to 1,286.09, 1,929.20 and 420.38

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Solution

The fourth proportional to 1,286.09, 1,929.20 and 420.38 is: 630.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.09 : 1,929.20 = 420.38 : x
  2. Step 2: Convert to fraction form
    1,286.09/1,929.20 = 420.38/x
  3. Step 3: Cross multiply
    1,286.09x = 1,929.20 × 420.38
  4. Step 4: Simplify right side
    1,286.09x = 810,985.35
  5. Step 5: Solve for x
    x = 810,985.35/1,286.09
  6. Step 6: Final answer
    x = 630.58

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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.