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Finding the Fourth Proportional to 990.09, 1,485.14 and 259.67

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Solution

The fourth proportional to 990.09, 1,485.14 and 259.67 is: 389.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.09 : 1,485.14 = 259.67 : x
  2. Step 2: Convert to fraction form
    990.09/1,485.14 = 259.67/x
  3. Step 3: Cross multiply
    990.09x = 1,485.14 × 259.67
  4. Step 4: Simplify right side
    990.09x = 385,648.72
  5. Step 5: Solve for x
    x = 385,648.72/990.09
  6. Step 6: Final answer
    x = 389.51

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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.