Home / 1,389.82-1,920.68-1,242.20

Finding the Fourth Proportional to 1,389.82, 1,920.68 and 1,242.20

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Solution

The fourth proportional to 1,389.82, 1,920.68 and 1,242.20 is: 1,716.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.82 : 1,920.68 = 1,242.20 : x
  2. Step 2: Convert to fraction form
    1,389.82/1,920.68 = 1,242.20/x
  3. Step 3: Cross multiply
    1,389.82x = 1,920.68 × 1,242.20
  4. Step 4: Simplify right side
    1,389.82x = 2,385,868.70
  5. Step 5: Solve for x
    x = 2,385,868.70/1,389.82
  6. Step 6: Final answer
    x = 1,716.67

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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.