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Finding the Fourth Proportional to 990.31, 1,485.28 and 442.39

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Solution

The fourth proportional to 990.31, 1,485.28 and 442.39 is: 663.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.31 : 1,485.28 = 442.39 : x
  2. Step 2: Convert to fraction form
    990.31/1,485.28 = 442.39/x
  3. Step 3: Cross multiply
    990.31x = 1,485.28 × 442.39
  4. Step 4: Simplify right side
    990.31x = 657,073.02
  5. Step 5: Solve for x
    x = 657,073.02/990.31
  6. Step 6: Final answer
    x = 663.50

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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.