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Finding the Fourth Proportional to 806.15, 1,211.93 and 643.67

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Solution

The fourth proportional to 806.15, 1,211.93 and 643.67 is: 967.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.15 : 1,211.93 = 643.67 : x
  2. Step 2: Convert to fraction form
    806.15/1,211.93 = 643.67/x
  3. Step 3: Cross multiply
    806.15x = 1,211.93 × 643.67
  4. Step 4: Simplify right side
    806.15x = 780,073.71
  5. Step 5: Solve for x
    x = 780,073.71/806.15
  6. Step 6: Final answer
    x = 967.65

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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.