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Finding the Fourth Proportional to 1,280.02, 1,918.80 and 621.13

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Solution

The fourth proportional to 1,280.02, 1,918.80 and 621.13 is: 931.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.02 : 1,918.80 = 621.13 : x
  2. Step 2: Convert to fraction form
    1,280.02/1,918.80 = 621.13/x
  3. Step 3: Cross multiply
    1,280.02x = 1,918.80 × 621.13
  4. Step 4: Simplify right side
    1,280.02x = 1,191,812.57
  5. Step 5: Solve for x
    x = 1,191,812.57/1,280.02
  6. Step 6: Final answer
    x = 931.09

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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.