Home / 1,286.61-1,929.69-420.81

Finding the Fourth Proportional to 1,286.61, 1,929.69 and 420.81

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Solution

The fourth proportional to 1,286.61, 1,929.69 and 420.81 is: 631.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.61 : 1,929.69 = 420.81 : x
  2. Step 2: Convert to fraction form
    1,286.61/1,929.69 = 420.81/x
  3. Step 3: Cross multiply
    1,286.61x = 1,929.69 × 420.81
  4. Step 4: Simplify right side
    1,286.61x = 812,032.85
  5. Step 5: Solve for x
    x = 812,032.85/1,286.61
  6. Step 6: Final answer
    x = 631.14

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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.