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Finding the Fourth Proportional to 687.79, 948.81 and 638.38

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Solution

The fourth proportional to 687.79, 948.81 and 638.38 is: 880.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.79 : 948.81 = 638.38 : x
  2. Step 2: Convert to fraction form
    687.79/948.81 = 638.38/x
  3. Step 3: Cross multiply
    687.79x = 948.81 × 638.38
  4. Step 4: Simplify right side
    687.79x = 605,701.33
  5. Step 5: Solve for x
    x = 605,701.33/687.79
  6. Step 6: Final answer
    x = 880.65

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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.