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Finding the Fourth Proportional to 852.78, 1,279.34 and 390.78

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Solution

The fourth proportional to 852.78, 1,279.34 and 390.78 is: 586.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    852.78 : 1,279.34 = 390.78 : x
  2. Step 2: Convert to fraction form
    852.78/1,279.34 = 390.78/x
  3. Step 3: Cross multiply
    852.78x = 1,279.34 × 390.78
  4. Step 4: Simplify right side
    852.78x = 499,940.49
  5. Step 5: Solve for x
    x = 499,940.49/852.78
  6. Step 6: Final answer
    x = 586.25

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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.