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Finding the Fourth Proportional to 990.12, 1,485.20 and 374.12

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Solution

The fourth proportional to 990.12, 1,485.20 and 374.12 is: 561.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.12 : 1,485.20 = 374.12 : x
  2. Step 2: Convert to fraction form
    990.12/1,485.20 = 374.12/x
  3. Step 3: Cross multiply
    990.12x = 1,485.20 × 374.12
  4. Step 4: Simplify right side
    990.12x = 555,633.73
  5. Step 5: Solve for x
    x = 555,633.73/990.12
  6. Step 6: Final answer
    x = 561.18

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Double scale
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Similar ratio
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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.