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Finding the Fourth Proportional to 1,815.50, 2,505.40 and 987.50

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Solution

The fourth proportional to 1,815.50, 2,505.40 and 987.50 is: 1,362.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,815.50 : 2,505.40 = 987.50 : x
  2. Step 2: Convert to fraction form
    1,815.50/2,505.40 = 987.50/x
  3. Step 3: Cross multiply
    1,815.50x = 2,505.40 × 987.50
  4. Step 4: Simplify right side
    1,815.50x = 2,474,082.50
  5. Step 5: Solve for x
    x = 2,474,082.50/1,815.50
  6. Step 6: Final answer
    x = 1,362.76

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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.