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Finding the Fourth Proportional to 878.75, 1,212.70 and 485.79

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Solution

The fourth proportional to 878.75, 1,212.70 and 485.79 is: 670.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.75 : 1,212.70 = 485.79 : x
  2. Step 2: Convert to fraction form
    878.75/1,212.70 = 485.79/x
  3. Step 3: Cross multiply
    878.75x = 1,212.70 × 485.79
  4. Step 4: Simplify right side
    878.75x = 589,116.32
  5. Step 5: Solve for x
    x = 589,116.32/878.75
  6. Step 6: Final answer
    x = 670.41

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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.