Home / 1,370.30-1,890.84-780.80

Finding the Fourth Proportional to 1,370.30, 1,890.84 and 780.80

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Solution

The fourth proportional to 1,370.30, 1,890.84 and 780.80 is: 1,077.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,370.30 : 1,890.84 = 780.80 : x
  2. Step 2: Convert to fraction form
    1,370.30/1,890.84 = 780.80/x
  3. Step 3: Cross multiply
    1,370.30x = 1,890.84 × 780.80
  4. Step 4: Simplify right side
    1,370.30x = 1,476,367.87
  5. Step 5: Solve for x
    x = 1,476,367.87/1,370.30
  6. Step 6: Final answer
    x = 1,077.40

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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.