Home / 1,279.80-1,769.58-1,115.78

Finding the Fourth Proportional to 1,279.80, 1,769.58 and 1,115.78

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Solution

The fourth proportional to 1,279.80, 1,769.58 and 1,115.78 is: 1,542.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.80 : 1,769.58 = 1,115.78 : x
  2. Step 2: Convert to fraction form
    1,279.80/1,769.58 = 1,115.78/x
  3. Step 3: Cross multiply
    1,279.80x = 1,769.58 × 1,115.78
  4. Step 4: Simplify right side
    1,279.80x = 1,974,453.12
  5. Step 5: Solve for x
    x = 1,974,453.12/1,279.80
  6. Step 6: Final answer
    x = 1,542.78

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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.