Home / 1,389.43-1,915-1,211.28

Finding the Fourth Proportional to 1,389.43, 1,915 and 1,211.28

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Solution

The fourth proportional to 1,389.43, 1,915 and 1,211.28 is: 1,669.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.43 : 1,915 = 1,211.28 : x
  2. Step 2: Convert to fraction form
    1,389.43/1,915 = 1,211.28/x
  3. Step 3: Cross multiply
    1,389.43x = 1,915 × 1,211.28
  4. Step 4: Simplify right side
    1,389.43x = 2,319,591.63
  5. Step 5: Solve for x
    x = 2,319,591.63/1,389.43
  6. Step 6: Final answer
    x = 1,669.46

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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.