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Finding the Fourth Proportional to 639.39, 882.85 and 490.40

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Solution

The fourth proportional to 639.39, 882.85 and 490.40 is: 677.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.39 : 882.85 = 490.40 : x
  2. Step 2: Convert to fraction form
    639.39/882.85 = 490.40/x
  3. Step 3: Cross multiply
    639.39x = 882.85 × 490.40
  4. Step 4: Simplify right side
    639.39x = 432,953.20
  5. Step 5: Solve for x
    x = 432,953.20/639.39
  6. Step 6: Final answer
    x = 677.13

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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.