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Finding the Fourth Proportional to 1,279.56, 1,920.12 and 858.36

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Solution

The fourth proportional to 1,279.56, 1,920.12 and 858.36 is: 1,288.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.56 : 1,920.12 = 858.36 : x
  2. Step 2: Convert to fraction form
    1,279.56/1,920.12 = 858.36/x
  3. Step 3: Cross multiply
    1,279.56x = 1,920.12 × 858.36
  4. Step 4: Simplify right side
    1,279.56x = 1,648,154.20
  5. Step 5: Solve for x
    x = 1,648,154.20/1,279.56
  6. Step 6: Final answer
    x = 1,288.06

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1.5x scale

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.