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Finding the Fourth Proportional to 1,115, 1,538.80 and 649.34

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Solution

The fourth proportional to 1,115, 1,538.80 and 649.34 is: 896.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,115 : 1,538.80 = 649.34 : x
  2. Step 2: Convert to fraction form
    1,115/1,538.80 = 649.34/x
  3. Step 3: Cross multiply
    1,115x = 1,538.80 × 649.34
  4. Step 4: Simplify right side
    1,115x = 999,204.39
  5. Step 5: Solve for x
    x = 999,204.39/1,115
  6. Step 6: Final answer
    x = 896.15

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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.