Home / 1,390.12-1,918.38-800.80

Finding the Fourth Proportional to 1,390.12, 1,918.38 and 800.80

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Solution

The fourth proportional to 1,390.12, 1,918.38 and 800.80 is: 1,105.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.12 : 1,918.38 = 800.80 : x
  2. Step 2: Convert to fraction form
    1,390.12/1,918.38 = 800.80/x
  3. Step 3: Cross multiply
    1,390.12x = 1,918.38 × 800.80
  4. Step 4: Simplify right side
    1,390.12x = 1,536,238.70
  5. Step 5: Solve for x
    x = 1,536,238.70/1,390.12
  6. Step 6: Final answer
    x = 1,105.11

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.