Home / 1,287.39-1,931.10-421.50

Finding the Fourth Proportional to 1,287.39, 1,931.10 and 421.50

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Solution

The fourth proportional to 1,287.39, 1,931.10 and 421.50 is: 632.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.39 : 1,931.10 = 421.50 : x
  2. Step 2: Convert to fraction form
    1,287.39/1,931.10 = 421.50/x
  3. Step 3: Cross multiply
    1,287.39x = 1,931.10 × 421.50
  4. Step 4: Simplify right side
    1,287.39x = 813,958.65
  5. Step 5: Solve for x
    x = 813,958.65/1,287.39
  6. Step 6: Final answer
    x = 632.25

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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.