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Finding the Fourth Proportional to 990.15, 1,485.80 and 913.65

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Solution

The fourth proportional to 990.15, 1,485.80 and 913.65 is: 1,371.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.15 : 1,485.80 = 913.65 : x
  2. Step 2: Convert to fraction form
    990.15/1,485.80 = 913.65/x
  3. Step 3: Cross multiply
    990.15x = 1,485.80 × 913.65
  4. Step 4: Simplify right side
    990.15x = 1,357,501.17
  5. Step 5: Solve for x
    x = 1,357,501.17/990.15
  6. Step 6: Final answer
    x = 1,371.01

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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.