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Finding the Fourth Proportional to 639.64, 881.88 and 521.20

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Solution

The fourth proportional to 639.64, 881.88 and 521.20 is: 718.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.64 : 881.88 = 521.20 : x
  2. Step 2: Convert to fraction form
    639.64/881.88 = 521.20/x
  3. Step 3: Cross multiply
    639.64x = 881.88 × 521.20
  4. Step 4: Simplify right side
    639.64x = 459,635.86
  5. Step 5: Solve for x
    x = 459,635.86/639.64
  6. Step 6: Final answer
    x = 718.59

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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.