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Finding the Fourth Proportional to 905.78, 1,249.89 and 719.72

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Solution

The fourth proportional to 905.78, 1,249.89 and 719.72 is: 993.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.78 : 1,249.89 = 719.72 : x
  2. Step 2: Convert to fraction form
    905.78/1,249.89 = 719.72/x
  3. Step 3: Cross multiply
    905.78x = 1,249.89 × 719.72
  4. Step 4: Simplify right side
    905.78x = 899,570.83
  5. Step 5: Solve for x
    x = 899,570.83/905.78
  6. Step 6: Final answer
    x = 993.14

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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.