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Finding the Fourth Proportional to 855.84, 1,284 and 393.76

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Solution

The fourth proportional to 855.84, 1,284 and 393.76 is: 590.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.84 : 1,284 = 393.76 : x
  2. Step 2: Convert to fraction form
    855.84/1,284 = 393.76/x
  3. Step 3: Cross multiply
    855.84x = 1,284 × 393.76
  4. Step 4: Simplify right side
    855.84x = 505,587.84
  5. Step 5: Solve for x
    x = 505,587.84/855.84
  6. Step 6: Final answer
    x = 590.75

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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.