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Finding the Fourth Proportional to 1,127.72, 1,690.72 and 780.13

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Solution

The fourth proportional to 1,127.72, 1,690.72 and 780.13 is: 1,169.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,127.72 : 1,690.72 = 780.13 : x
  2. Step 2: Convert to fraction form
    1,127.72/1,690.72 = 780.13/x
  3. Step 3: Cross multiply
    1,127.72x = 1,690.72 × 780.13
  4. Step 4: Simplify right side
    1,127.72x = 1,318,969.04
  5. Step 5: Solve for x
    x = 1,318,969.04/1,127.72
  6. Step 6: Final answer
    x = 1,169.59

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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.