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Finding the Fourth Proportional to 856.56, 1,282.28 and 639.60

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Solution

The fourth proportional to 856.56, 1,282.28 and 639.60 is: 957.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.56 : 1,282.28 = 639.60 : x
  2. Step 2: Convert to fraction form
    856.56/1,282.28 = 639.60/x
  3. Step 3: Cross multiply
    856.56x = 1,282.28 × 639.60
  4. Step 4: Simplify right side
    856.56x = 820,146.29
  5. Step 5: Solve for x
    x = 820,146.29/856.56
  6. Step 6: Final answer
    x = 957.49

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.