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Finding the Fourth Proportional to 1,085.78, 1,498.44 and 643.58

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Solution

The fourth proportional to 1,085.78, 1,498.44 and 643.58 is: 888.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,085.78 : 1,498.44 = 643.58 : x
  2. Step 2: Convert to fraction form
    1,085.78/1,498.44 = 643.58/x
  3. Step 3: Cross multiply
    1,085.78x = 1,498.44 × 643.58
  4. Step 4: Simplify right side
    1,085.78x = 964,366.02
  5. Step 5: Solve for x
    x = 964,366.02/1,085.78
  6. Step 6: Final answer
    x = 888.18

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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.