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Finding the Fourth Proportional to 620.80, 856.70 and 388.04

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Solution

The fourth proportional to 620.80, 856.70 and 388.04 is: 535.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.80 : 856.70 = 388.04 : x
  2. Step 2: Convert to fraction form
    620.80/856.70 = 388.04/x
  3. Step 3: Cross multiply
    620.80x = 856.70 × 388.04
  4. Step 4: Simplify right side
    620.80x = 332,433.87
  5. Step 5: Solve for x
    x = 332,433.87/620.80
  6. Step 6: Final answer
    x = 535.49

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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.