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Finding the Fourth Proportional to 859.85, 1,290.46 and 312.19

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Solution

The fourth proportional to 859.85, 1,290.46 and 312.19 is: 468.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.85 : 1,290.46 = 312.19 : x
  2. Step 2: Convert to fraction form
    859.85/1,290.46 = 312.19/x
  3. Step 3: Cross multiply
    859.85x = 1,290.46 × 312.19
  4. Step 4: Simplify right side
    859.85x = 402,868.71
  5. Step 5: Solve for x
    x = 402,868.71/859.85
  6. Step 6: Final answer
    x = 468.53

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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.