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Finding the Fourth Proportional to 860.31, 1,289.66 and 312.21

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Solution

The fourth proportional to 860.31, 1,289.66 and 312.21 is: 468.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.31 : 1,289.66 = 312.21 : x
  2. Step 2: Convert to fraction form
    860.31/1,289.66 = 312.21/x
  3. Step 3: Cross multiply
    860.31x = 1,289.66 × 312.21
  4. Step 4: Simplify right side
    860.31x = 402,643.19
  5. Step 5: Solve for x
    x = 402,643.19/860.31
  6. Step 6: Final answer
    x = 468.02

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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.