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Finding the Fourth Proportional to 780.31, 1,169.95 and 318

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Solution

The fourth proportional to 780.31, 1,169.95 and 318 is: 476.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.31 : 1,169.95 = 318 : x
  2. Step 2: Convert to fraction form
    780.31/1,169.95 = 318/x
  3. Step 3: Cross multiply
    780.31x = 1,169.95 × 318
  4. Step 4: Simplify right side
    780.31x = 372,044.10
  5. Step 5: Solve for x
    x = 372,044.10/780.31
  6. Step 6: Final answer
    x = 476.79

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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.