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Finding the Fourth Proportional to 860.18, 1,289.94 and 312.21

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Solution

The fourth proportional to 860.18, 1,289.94 and 312.21 is: 468.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.18 : 1,289.94 = 312.21 : x
  2. Step 2: Convert to fraction form
    860.18/1,289.94 = 312.21/x
  3. Step 3: Cross multiply
    860.18x = 1,289.94 × 312.21
  4. Step 4: Simplify right side
    860.18x = 402,732.17
  5. Step 5: Solve for x
    x = 402,732.17/860.18
  6. Step 6: Final answer
    x = 468.20

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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.