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Finding the Fourth Proportional to 287.70, 431.57 and 90.02

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Solution

The fourth proportional to 287.70, 431.57 and 90.02 is: 135.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.70 : 431.57 = 90.02 : x
  2. Step 2: Convert to fraction form
    287.70/431.57 = 90.02/x
  3. Step 3: Cross multiply
    287.70x = 431.57 × 90.02
  4. Step 4: Simplify right side
    287.70x = 38,849.93
  5. Step 5: Solve for x
    x = 38,849.93/287.70
  6. Step 6: Final answer
    x = 135.04

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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.