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Finding the Fourth Proportional to 1,369.79, 1,890.51 and 780.38

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Solution

The fourth proportional to 1,369.79, 1,890.51 and 780.38 is: 1,077.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,369.79 : 1,890.51 = 780.38 : x
  2. Step 2: Convert to fraction form
    1,369.79/1,890.51 = 780.38/x
  3. Step 3: Cross multiply
    1,369.79x = 1,890.51 × 780.38
  4. Step 4: Simplify right side
    1,369.79x = 1,475,312.29
  5. Step 5: Solve for x
    x = 1,475,312.29/1,369.79
  6. Step 6: Final answer
    x = 1,077.04

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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.