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Finding the Fourth Proportional to 860.49, 1,290.71 and 312.68

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Solution

The fourth proportional to 860.49, 1,290.71 and 312.68 is: 469.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.49 : 1,290.71 = 312.68 : x
  2. Step 2: Convert to fraction form
    860.49/1,290.71 = 312.68/x
  3. Step 3: Cross multiply
    860.49x = 1,290.71 × 312.68
  4. Step 4: Simplify right side
    860.49x = 403,583.21
  5. Step 5: Solve for x
    x = 403,583.21/860.49
  6. Step 6: Final answer
    x = 469.02

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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.