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Finding the Fourth Proportional to 990.84, 1,485.30 and 413.40

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Solution

The fourth proportional to 990.84, 1,485.30 and 413.40 is: 619.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.84 : 1,485.30 = 413.40 : x
  2. Step 2: Convert to fraction form
    990.84/1,485.30 = 413.40/x
  3. Step 3: Cross multiply
    990.84x = 1,485.30 × 413.40
  4. Step 4: Simplify right side
    990.84x = 614,023.02
  5. Step 5: Solve for x
    x = 614,023.02/990.84
  6. Step 6: Final answer
    x = 619.70

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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.