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Finding the Fourth Proportional to 643.40, 888.19 and 620.31

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Solution

The fourth proportional to 643.40, 888.19 and 620.31 is: 856.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.40 : 888.19 = 620.31 : x
  2. Step 2: Convert to fraction form
    643.40/888.19 = 620.31/x
  3. Step 3: Cross multiply
    643.40x = 888.19 × 620.31
  4. Step 4: Simplify right side
    643.40x = 550,954.92
  5. Step 5: Solve for x
    x = 550,954.92/643.40
  6. Step 6: Final answer
    x = 856.32

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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.