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Finding the Fourth Proportional to 620.40, 856.50 and 387.84

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Solution

The fourth proportional to 620.40, 856.50 and 387.84 is: 535.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.40 : 856.50 = 387.84 : x
  2. Step 2: Convert to fraction form
    620.40/856.50 = 387.84/x
  3. Step 3: Cross multiply
    620.40x = 856.50 × 387.84
  4. Step 4: Simplify right side
    620.40x = 332,184.96
  5. Step 5: Solve for x
    x = 332,184.96/620.40
  6. Step 6: Final answer
    x = 535.44

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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.