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Finding the Fourth Proportional to 1,320, 1,979.76 and 857.46

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Solution

The fourth proportional to 1,320, 1,979.76 and 857.46 is: 1,286.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,320 : 1,979.76 = 857.46 : x
  2. Step 2: Convert to fraction form
    1,320/1,979.76 = 857.46/x
  3. Step 3: Cross multiply
    1,320x = 1,979.76 × 857.46
  4. Step 4: Simplify right side
    1,320x = 1,697,565.01
  5. Step 5: Solve for x
    x = 1,697,565.01/1,320
  6. Step 6: Final answer
    x = 1,286.03

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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.