Home / 1,421.15-1,960.40-890.80

Finding the Fourth Proportional to 1,421.15, 1,960.40 and 890.80

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Solution

The fourth proportional to 1,421.15, 1,960.40 and 890.80 is: 1,228.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.15 : 1,960.40 = 890.80 : x
  2. Step 2: Convert to fraction form
    1,421.15/1,960.40 = 890.80/x
  3. Step 3: Cross multiply
    1,421.15x = 1,960.40 × 890.80
  4. Step 4: Simplify right side
    1,421.15x = 1,746,321.65
  5. Step 5: Solve for x
    x = 1,746,321.65/1,421.15
  6. Step 6: Final answer
    x = 1,228.81

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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.