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Finding the Fourth Proportional to 639.40, 956.70 and 581.80

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Solution

The fourth proportional to 639.40, 956.70 and 581.80 is: 870.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.40 : 956.70 = 581.80 : x
  2. Step 2: Convert to fraction form
    639.40/956.70 = 581.80/x
  3. Step 3: Cross multiply
    639.40x = 956.70 × 581.80
  4. Step 4: Simplify right side
    639.40x = 556,608.06
  5. Step 5: Solve for x
    x = 556,608.06/639.40
  6. Step 6: Final answer
    x = 870.52

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.