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Finding the Fourth Proportional to 1,311.72, 1,810.65 and 869.77

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Solution

The fourth proportional to 1,311.72, 1,810.65 and 869.77 is: 1,200.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.72 : 1,810.65 = 869.77 : x
  2. Step 2: Convert to fraction form
    1,311.72/1,810.65 = 869.77/x
  3. Step 3: Cross multiply
    1,311.72x = 1,810.65 × 869.77
  4. Step 4: Simplify right side
    1,311.72x = 1,574,849.05
  5. Step 5: Solve for x
    x = 1,574,849.05/1,311.72
  6. Step 6: Final answer
    x = 1,200.60

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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.