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Finding the Fourth Proportional to 860.42, 1,291.17 and 312.59

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Solution

The fourth proportional to 860.42, 1,291.17 and 312.59 is: 469.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.42 : 1,291.17 = 312.59 : x
  2. Step 2: Convert to fraction form
    860.42/1,291.17 = 312.59/x
  3. Step 3: Cross multiply
    860.42x = 1,291.17 × 312.59
  4. Step 4: Simplify right side
    860.42x = 403,611.23
  5. Step 5: Solve for x
    x = 403,611.23/860.42
  6. Step 6: Final answer
    x = 469.08

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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.