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Finding the Fourth Proportional to 781.10, 1,078.36 and 623.23

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Solution

The fourth proportional to 781.10, 1,078.36 and 623.23 is: 860.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.10 : 1,078.36 = 623.23 : x
  2. Step 2: Convert to fraction form
    781.10/1,078.36 = 623.23/x
  3. Step 3: Cross multiply
    781.10x = 1,078.36 × 623.23
  4. Step 4: Simplify right side
    781.10x = 672,057.79
  5. Step 5: Solve for x
    x = 672,057.79/781.10
  6. Step 6: Final answer
    x = 860.40

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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.