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Finding the Fourth Proportional to 782.72, 1,079.42 and 487.78

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Solution

The fourth proportional to 782.72, 1,079.42 and 487.78 is: 672.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.72 : 1,079.42 = 487.78 : x
  2. Step 2: Convert to fraction form
    782.72/1,079.42 = 487.78/x
  3. Step 3: Cross multiply
    782.72x = 1,079.42 × 487.78
  4. Step 4: Simplify right side
    782.72x = 526,519.49
  5. Step 5: Solve for x
    x = 526,519.49/782.72
  6. Step 6: Final answer
    x = 672.68

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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.