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Finding the Fourth Proportional to 1,127.79, 1,690.52 and 639.81

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Solution

The fourth proportional to 1,127.79, 1,690.52 and 639.81 is: 959.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,127.79 : 1,690.52 = 639.81 : x
  2. Step 2: Convert to fraction form
    1,127.79/1,690.52 = 639.81/x
  3. Step 3: Cross multiply
    1,127.79x = 1,690.52 × 639.81
  4. Step 4: Simplify right side
    1,127.79x = 1,081,608.40
  5. Step 5: Solve for x
    x = 1,081,608.40/1,127.79
  6. Step 6: Final answer
    x = 959.05

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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.