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Finding the Fourth Proportional to 1,320.16, 1,980.08 and 408.16

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Solution

The fourth proportional to 1,320.16, 1,980.08 and 408.16 is: 612.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,320.16 : 1,980.08 = 408.16 : x
  2. Step 2: Convert to fraction form
    1,320.16/1,980.08 = 408.16/x
  3. Step 3: Cross multiply
    1,320.16x = 1,980.08 × 408.16
  4. Step 4: Simplify right side
    1,320.16x = 808,189.45
  5. Step 5: Solve for x
    x = 808,189.45/1,320.16
  6. Step 6: Final answer
    x = 612.19

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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.