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Finding the Fourth Proportional to 1,287.16, 1,776.76 and 868.70

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Solution

The fourth proportional to 1,287.16, 1,776.76 and 868.70 is: 1,199.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.16 : 1,776.76 = 868.70 : x
  2. Step 2: Convert to fraction form
    1,287.16/1,776.76 = 868.70/x
  3. Step 3: Cross multiply
    1,287.16x = 1,776.76 × 868.70
  4. Step 4: Simplify right side
    1,287.16x = 1,543,471.41
  5. Step 5: Solve for x
    x = 1,543,471.41/1,287.16
  6. Step 6: Final answer
    x = 1,199.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.