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Finding the Fourth Proportional to 878.72, 1,212.57 and 485.75

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Solution

The fourth proportional to 878.72, 1,212.57 and 485.75 is: 670.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.72 : 1,212.57 = 485.75 : x
  2. Step 2: Convert to fraction form
    878.72/1,212.57 = 485.75/x
  3. Step 3: Cross multiply
    878.72x = 1,212.57 × 485.75
  4. Step 4: Simplify right side
    878.72x = 589,005.88
  5. Step 5: Solve for x
    x = 589,005.88/878.72
  6. Step 6: Final answer
    x = 670.30

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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.