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Finding the Fourth Proportional to 825.66, 1,138.77 and 639.72

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Solution

The fourth proportional to 825.66, 1,138.77 and 639.72 is: 882.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.66 : 1,138.77 = 639.72 : x
  2. Step 2: Convert to fraction form
    825.66/1,138.77 = 639.72/x
  3. Step 3: Cross multiply
    825.66x = 1,138.77 × 639.72
  4. Step 4: Simplify right side
    825.66x = 728,493.94
  5. Step 5: Solve for x
    x = 728,493.94/825.66
  6. Step 6: Final answer
    x = 882.32

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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.