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Finding the Fourth Proportional to 986.20, 1,357.50 and 899.80

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Solution

The fourth proportional to 986.20, 1,357.50 and 899.80 is: 1,238.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.20 : 1,357.50 = 899.80 : x
  2. Step 2: Convert to fraction form
    986.20/1,357.50 = 899.80/x
  3. Step 3: Cross multiply
    986.20x = 1,357.50 × 899.80
  4. Step 4: Simplify right side
    986.20x = 1,221,478.50
  5. Step 5: Solve for x
    x = 1,221,478.50/986.20
  6. Step 6: Final answer
    x = 1,238.57

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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.