Home / 1,287.45-1,931.18-421.74

Finding the Fourth Proportional to 1,287.45, 1,931.18 and 421.74

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Solution

The fourth proportional to 1,287.45, 1,931.18 and 421.74 is: 632.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.45 : 1,931.18 = 421.74 : x
  2. Step 2: Convert to fraction form
    1,287.45/1,931.18 = 421.74/x
  3. Step 3: Cross multiply
    1,287.45x = 1,931.18 × 421.74
  4. Step 4: Simplify right side
    1,287.45x = 814,453.74
  5. Step 5: Solve for x
    x = 814,453.74/1,287.45
  6. Step 6: Final answer
    x = 632.61

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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.