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Finding the Fourth Proportional to 1,087.20, 1,500.39 and 645.12

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Solution

The fourth proportional to 1,087.20, 1,500.39 and 645.12 is: 890.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,087.20 : 1,500.39 = 645.12 : x
  2. Step 2: Convert to fraction form
    1,087.20/1,500.39 = 645.12/x
  3. Step 3: Cross multiply
    1,087.20x = 1,500.39 × 645.12
  4. Step 4: Simplify right side
    1,087.20x = 967,931.60
  5. Step 5: Solve for x
    x = 967,931.60/1,087.20
  6. Step 6: Final answer
    x = 890.30

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.