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Finding the Fourth Proportional to 905.69, 1,249.85 and 491.69

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Solution

The fourth proportional to 905.69, 1,249.85 and 491.69 is: 678.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.69 : 1,249.85 = 491.69 : x
  2. Step 2: Convert to fraction form
    905.69/1,249.85 = 491.69/x
  3. Step 3: Cross multiply
    905.69x = 1,249.85 × 491.69
  4. Step 4: Simplify right side
    905.69x = 614,538.75
  5. Step 5: Solve for x
    x = 614,538.75/905.69
  6. Step 6: Final answer
    x = 678.53

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Half scale
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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.