Home / 1,287.40-1,931.46-421.68

Finding the Fourth Proportional to 1,287.40, 1,931.46 and 421.68

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Solution

The fourth proportional to 1,287.40, 1,931.46 and 421.68 is: 632.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.40 : 1,931.46 = 421.68 : x
  2. Step 2: Convert to fraction form
    1,287.40/1,931.46 = 421.68/x
  3. Step 3: Cross multiply
    1,287.40x = 1,931.46 × 421.68
  4. Step 4: Simplify right side
    1,287.40x = 814,458.05
  5. Step 5: Solve for x
    x = 814,458.05/1,287.40
  6. Step 6: Final answer
    x = 632.64

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1.5x scale

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.