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Finding the Fourth Proportional to 990.18, 1,485.90 and 579.51

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Solution

The fourth proportional to 990.18, 1,485.90 and 579.51 is: 869.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.18 : 1,485.90 = 579.51 : x
  2. Step 2: Convert to fraction form
    990.18/1,485.90 = 579.51/x
  3. Step 3: Cross multiply
    990.18x = 1,485.90 × 579.51
  4. Step 4: Simplify right side
    990.18x = 861,093.91
  5. Step 5: Solve for x
    x = 861,093.91/990.18
  6. Step 6: Final answer
    x = 869.63

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Double scale
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1.5x scale

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.