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Finding the Fourth Proportional to 1,409.91, 1,945.79 and 780.64

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Solution

The fourth proportional to 1,409.91, 1,945.79 and 780.64 is: 1,077.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,409.91 : 1,945.79 = 780.64 : x
  2. Step 2: Convert to fraction form
    1,409.91/1,945.79 = 780.64/x
  3. Step 3: Cross multiply
    1,409.91x = 1,945.79 × 780.64
  4. Step 4: Simplify right side
    1,409.91x = 1,518,952.74
  5. Step 5: Solve for x
    x = 1,518,952.74/1,409.91
  6. Step 6: Final answer
    x = 1,077.34

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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.