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Finding the Fourth Proportional to 931.51, 1,397.67 and 643.42

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Solution

The fourth proportional to 931.51, 1,397.67 and 643.42 is: 965.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    931.51 : 1,397.67 = 643.42 : x
  2. Step 2: Convert to fraction form
    931.51/1,397.67 = 643.42/x
  3. Step 3: Cross multiply
    931.51x = 1,397.67 × 643.42
  4. Step 4: Simplify right side
    931.51x = 899,288.83
  5. Step 5: Solve for x
    x = 899,288.83/931.51
  6. Step 6: Final answer
    x = 965.41

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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.