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Finding the Fourth Proportional to 1,287.34, 1,931.07 and 421.63

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Solution

The fourth proportional to 1,287.34, 1,931.07 and 421.63 is: 632.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.34 : 1,931.07 = 421.63 : x
  2. Step 2: Convert to fraction form
    1,287.34/1,931.07 = 421.63/x
  3. Step 3: Cross multiply
    1,287.34x = 1,931.07 × 421.63
  4. Step 4: Simplify right side
    1,287.34x = 814,197.04
  5. Step 5: Solve for x
    x = 814,197.04/1,287.34
  6. Step 6: Final answer
    x = 632.46

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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.