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Finding the Fourth Proportional to 878.67, 1,213.02 and 642.35

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Solution

The fourth proportional to 878.67, 1,213.02 and 642.35 is: 886.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.67 : 1,213.02 = 642.35 : x
  2. Step 2: Convert to fraction form
    878.67/1,213.02 = 642.35/x
  3. Step 3: Cross multiply
    878.67x = 1,213.02 × 642.35
  4. Step 4: Simplify right side
    878.67x = 779,177.33
  5. Step 5: Solve for x
    x = 779,177.33/878.67
  6. Step 6: Final answer
    x = 886.77

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.