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Finding the Fourth Proportional to 857.79, 1,287.50 and 395.89

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Solution

The fourth proportional to 857.79, 1,287.50 and 395.89 is: 594.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.79 : 1,287.50 = 395.89 : x
  2. Step 2: Convert to fraction form
    857.79/1,287.50 = 395.89/x
  3. Step 3: Cross multiply
    857.79x = 1,287.50 × 395.89
  4. Step 4: Simplify right side
    857.79x = 509,703.18
  5. Step 5: Solve for x
    x = 509,703.18/857.79
  6. Step 6: Final answer
    x = 594.21

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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.