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Finding the Fourth Proportional to 852.55, 1,279.02 and 390.40

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Solution

The fourth proportional to 852.55, 1,279.02 and 390.40 is: 585.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    852.55 : 1,279.02 = 390.40 : x
  2. Step 2: Convert to fraction form
    852.55/1,279.02 = 390.40/x
  3. Step 3: Cross multiply
    852.55x = 1,279.02 × 390.40
  4. Step 4: Simplify right side
    852.55x = 499,329.41
  5. Step 5: Solve for x
    x = 499,329.41/852.55
  6. Step 6: Final answer
    x = 585.69

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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.