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Finding the Fourth Proportional to 620.58, 856.59 and 387.90

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Solution

The fourth proportional to 620.58, 856.59 and 387.90 is: 535.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.58 : 856.59 = 387.90 : x
  2. Step 2: Convert to fraction form
    620.58/856.59 = 387.90/x
  3. Step 3: Cross multiply
    620.58x = 856.59 × 387.90
  4. Step 4: Simplify right side
    620.58x = 332,271.26
  5. Step 5: Solve for x
    x = 332,271.26/620.58
  6. Step 6: Final answer
    x = 535.42

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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.