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Finding the Fourth Proportional to 678.51, 1,017.45 and 209.93

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Solution

The fourth proportional to 678.51, 1,017.45 and 209.93 is: 314.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.51 : 1,017.45 = 209.93 : x
  2. Step 2: Convert to fraction form
    678.51/1,017.45 = 209.93/x
  3. Step 3: Cross multiply
    678.51x = 1,017.45 × 209.93
  4. Step 4: Simplify right side
    678.51x = 213,588.19
  5. Step 5: Solve for x
    x = 213,588.19/678.51
  6. Step 6: Final answer
    x = 314.79

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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.