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Finding the Fourth Proportional to 958.40, 1,322.10 and 643.25

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Solution

The fourth proportional to 958.40, 1,322.10 and 643.25 is: 887.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    958.40 : 1,322.10 = 643.25 : x
  2. Step 2: Convert to fraction form
    958.40/1,322.10 = 643.25/x
  3. Step 3: Cross multiply
    958.40x = 1,322.10 × 643.25
  4. Step 4: Simplify right side
    958.40x = 850,444.13
  5. Step 5: Solve for x
    x = 850,444.13/958.40
  6. Step 6: Final answer
    x = 887.36

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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.