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Finding the Fourth Proportional to 1,239.16, 1,709.74 and 687.16

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Solution

The fourth proportional to 1,239.16, 1,709.74 and 687.16 is: 948.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.16 : 1,709.74 = 687.16 : x
  2. Step 2: Convert to fraction form
    1,239.16/1,709.74 = 687.16/x
  3. Step 3: Cross multiply
    1,239.16x = 1,709.74 × 687.16
  4. Step 4: Simplify right side
    1,239.16x = 1,174,864.94
  5. Step 5: Solve for x
    x = 1,174,864.94/1,239.16
  6. Step 6: Final answer
    x = 948.11

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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.