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Finding the Fourth Proportional to 890.86, 1,228.76 and 638.56

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Solution

The fourth proportional to 890.86, 1,228.76 and 638.56 is: 880.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.86 : 1,228.76 = 638.56 : x
  2. Step 2: Convert to fraction form
    890.86/1,228.76 = 638.56/x
  3. Step 3: Cross multiply
    890.86x = 1,228.76 × 638.56
  4. Step 4: Simplify right side
    890.86x = 784,636.99
  5. Step 5: Solve for x
    x = 784,636.99/890.86
  6. Step 6: Final answer
    x = 880.76

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Double scale
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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.