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Finding the Fourth Proportional to 1,288.19, 1,777.05 and 815.30

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Solution

The fourth proportional to 1,288.19, 1,777.05 and 815.30 is: 1,124.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.19 : 1,777.05 = 815.30 : x
  2. Step 2: Convert to fraction form
    1,288.19/1,777.05 = 815.30/x
  3. Step 3: Cross multiply
    1,288.19x = 1,777.05 × 815.30
  4. Step 4: Simplify right side
    1,288.19x = 1,448,819.98
  5. Step 5: Solve for x
    x = 1,448,819.98/1,288.19
  6. Step 6: Final answer
    x = 1,124.69

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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.