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Finding the Fourth Proportional to 856.78, 1,285.18 and 279.66

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Solution

The fourth proportional to 856.78, 1,285.18 and 279.66 is: 419.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.78 : 1,285.18 = 279.66 : x
  2. Step 2: Convert to fraction form
    856.78/1,285.18 = 279.66/x
  3. Step 3: Cross multiply
    856.78x = 1,285.18 × 279.66
  4. Step 4: Simplify right side
    856.78x = 359,413.44
  5. Step 5: Solve for x
    x = 359,413.44/856.78
  6. Step 6: Final answer
    x = 419.49

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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.