Home / 1,287.56-1,931.50-421.64

Finding the Fourth Proportional to 1,287.56, 1,931.50 and 421.64

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Solution

The fourth proportional to 1,287.56, 1,931.50 and 421.64 is: 632.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.56 : 1,931.50 = 421.64 : x
  2. Step 2: Convert to fraction form
    1,287.56/1,931.50 = 421.64/x
  3. Step 3: Cross multiply
    1,287.56x = 1,931.50 × 421.64
  4. Step 4: Simplify right side
    1,287.56x = 814,397.66
  5. Step 5: Solve for x
    x = 814,397.66/1,287.56
  6. Step 6: Final answer
    x = 632.51

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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.