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Finding the Fourth Proportional to 958.60, 1,321.50 and 643.30

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Solution

The fourth proportional to 958.60, 1,321.50 and 643.30 is: 886.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    958.60 : 1,321.50 = 643.30 : x
  2. Step 2: Convert to fraction form
    958.60/1,321.50 = 643.30/x
  3. Step 3: Cross multiply
    958.60x = 1,321.50 × 643.30
  4. Step 4: Simplify right side
    958.60x = 850,120.95
  5. Step 5: Solve for x
    x = 850,120.95/958.60
  6. Step 6: Final answer
    x = 886.84

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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.