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Finding the Fourth Proportional to 859.77, 1,289.79 and 312.30

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Solution

The fourth proportional to 859.77, 1,289.79 and 312.30 is: 468.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.77 : 1,289.79 = 312.30 : x
  2. Step 2: Convert to fraction form
    859.77/1,289.79 = 312.30/x
  3. Step 3: Cross multiply
    859.77x = 1,289.79 × 312.30
  4. Step 4: Simplify right side
    859.77x = 402,801.42
  5. Step 5: Solve for x
    x = 402,801.42/859.77
  6. Step 6: Final answer
    x = 468.50

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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.