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Finding the Fourth Proportional to 780.94, 1,171.42 and 312.36

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Solution

The fourth proportional to 780.94, 1,171.42 and 312.36 is: 468.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.94 : 1,171.42 = 312.36 : x
  2. Step 2: Convert to fraction form
    780.94/1,171.42 = 312.36/x
  3. Step 3: Cross multiply
    780.94x = 1,171.42 × 312.36
  4. Step 4: Simplify right side
    780.94x = 365,904.75
  5. Step 5: Solve for x
    x = 365,904.75/780.94
  6. Step 6: Final answer
    x = 468.54

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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.