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Finding the Fourth Proportional to 687.72, 948.42 and 638.04

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Solution

The fourth proportional to 687.72, 948.42 and 638.04 is: 879.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.72 : 948.42 = 638.04 : x
  2. Step 2: Convert to fraction form
    687.72/948.42 = 638.04/x
  3. Step 3: Cross multiply
    687.72x = 948.42 × 638.04
  4. Step 4: Simplify right side
    687.72x = 605,129.90
  5. Step 5: Solve for x
    x = 605,129.90/687.72
  6. Step 6: Final answer
    x = 879.91

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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.