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Finding the Fourth Proportional to 878.25, 1,211.92 and 485.28

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Solution

The fourth proportional to 878.25, 1,211.92 and 485.28 is: 669.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.25 : 1,211.92 = 485.28 : x
  2. Step 2: Convert to fraction form
    878.25/1,211.92 = 485.28/x
  3. Step 3: Cross multiply
    878.25x = 1,211.92 × 485.28
  4. Step 4: Simplify right side
    878.25x = 588,114.78
  5. Step 5: Solve for x
    x = 588,114.78/878.25
  6. Step 6: Final answer
    x = 669.64

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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.