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Finding the Fourth Proportional to 860.88, 1,290.98 and 312.90

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Solution

The fourth proportional to 860.88, 1,290.98 and 312.90 is: 469.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.88 : 1,290.98 = 312.90 : x
  2. Step 2: Convert to fraction form
    860.88/1,290.98 = 312.90/x
  3. Step 3: Cross multiply
    860.88x = 1,290.98 × 312.90
  4. Step 4: Simplify right side
    860.88x = 403,947.64
  5. Step 5: Solve for x
    x = 403,947.64/860.88
  6. Step 6: Final answer
    x = 469.23

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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.