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Finding the Fourth Proportional to 1,238.15, 1,708.65 and 678.63

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Solution

The fourth proportional to 1,238.15, 1,708.65 and 678.63 is: 936.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.15 : 1,708.65 = 678.63 : x
  2. Step 2: Convert to fraction form
    1,238.15/1,708.65 = 678.63/x
  3. Step 3: Cross multiply
    1,238.15x = 1,708.65 × 678.63
  4. Step 4: Simplify right side
    1,238.15x = 1,159,541.15
  5. Step 5: Solve for x
    x = 1,159,541.15/1,238.15
  6. Step 6: Final answer
    x = 936.51

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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.