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Finding the Fourth Proportional to 990.40, 1,485.15 and 340.68

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Solution

The fourth proportional to 990.40, 1,485.15 and 340.68 is: 510.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.40 : 1,485.15 = 340.68 : x
  2. Step 2: Convert to fraction form
    990.40/1,485.15 = 340.68/x
  3. Step 3: Cross multiply
    990.40x = 1,485.15 × 340.68
  4. Step 4: Simplify right side
    990.40x = 505,960.90
  5. Step 5: Solve for x
    x = 505,960.90/990.40
  6. Step 6: Final answer
    x = 510.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.