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Finding the Fourth Proportional to 891.48, 1,230.47 and 643.51

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Solution

The fourth proportional to 891.48, 1,230.47 and 643.51 is: 888.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.48 : 1,230.47 = 643.51 : x
  2. Step 2: Convert to fraction form
    891.48/1,230.47 = 643.51/x
  3. Step 3: Cross multiply
    891.48x = 1,230.47 × 643.51
  4. Step 4: Simplify right side
    891.48x = 791,819.75
  5. Step 5: Solve for x
    x = 791,819.75/891.48
  6. Step 6: Final answer
    x = 888.21

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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.