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Finding the Fourth Proportional to 918.65, 1,378.13 and 456.45

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Solution

The fourth proportional to 918.65, 1,378.13 and 456.45 is: 684.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.65 : 1,378.13 = 456.45 : x
  2. Step 2: Convert to fraction form
    918.65/1,378.13 = 456.45/x
  3. Step 3: Cross multiply
    918.65x = 1,378.13 × 456.45
  4. Step 4: Simplify right side
    918.65x = 629,045.16
  5. Step 5: Solve for x
    x = 629,045.16/918.65
  6. Step 6: Final answer
    x = 684.75

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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.