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Finding the Fourth Proportional to 1,388.79, 1,916.87 and 864.63

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Solution

The fourth proportional to 1,388.79, 1,916.87 and 864.63 is: 1,193.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.79 : 1,916.87 = 864.63 : x
  2. Step 2: Convert to fraction form
    1,388.79/1,916.87 = 864.63/x
  3. Step 3: Cross multiply
    1,388.79x = 1,916.87 × 864.63
  4. Step 4: Simplify right side
    1,388.79x = 1,657,378.98
  5. Step 5: Solve for x
    x = 1,657,378.98/1,388.79
  6. Step 6: Final answer
    x = 1,193.40

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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.