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Finding the Fourth Proportional to 891.72, 1,230.50 and 518.80

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Solution

The fourth proportional to 891.72, 1,230.50 and 518.80 is: 715.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.72 : 1,230.50 = 518.80 : x
  2. Step 2: Convert to fraction form
    891.72/1,230.50 = 518.80/x
  3. Step 3: Cross multiply
    891.72x = 1,230.50 × 518.80
  4. Step 4: Simplify right side
    891.72x = 638,383.40
  5. Step 5: Solve for x
    x = 638,383.40/891.72
  6. Step 6: Final answer
    x = 715.90

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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.