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Finding the Fourth Proportional to 639.78, 955.01 and 549.06

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Solution

The fourth proportional to 639.78, 955.01 and 549.06 is: 819.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.78 : 955.01 = 549.06 : x
  2. Step 2: Convert to fraction form
    639.78/955.01 = 549.06/x
  3. Step 3: Cross multiply
    639.78x = 955.01 × 549.06
  4. Step 4: Simplify right side
    639.78x = 524,355.05
  5. Step 5: Solve for x
    x = 524,355.05/639.78
  6. Step 6: Final answer
    x = 819.59

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.