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Finding the Fourth Proportional to 1,288.87, 1,778.64 and 699.40

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Solution

The fourth proportional to 1,288.87, 1,778.64 and 699.40 is: 965.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.87 : 1,778.64 = 699.40 : x
  2. Step 2: Convert to fraction form
    1,288.87/1,778.64 = 699.40/x
  3. Step 3: Cross multiply
    1,288.87x = 1,778.64 × 699.40
  4. Step 4: Simplify right side
    1,288.87x = 1,243,980.42
  5. Step 5: Solve for x
    x = 1,243,980.42/1,288.87
  6. Step 6: Final answer
    x = 965.17

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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.