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Finding the Fourth Proportional to 1,289.79, 1,779.50 and 785.75

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Solution

The fourth proportional to 1,289.79, 1,779.50 and 785.75 is: 1,084.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.79 : 1,779.50 = 785.75 : x
  2. Step 2: Convert to fraction form
    1,289.79/1,779.50 = 785.75/x
  3. Step 3: Cross multiply
    1,289.79x = 1,779.50 × 785.75
  4. Step 4: Simplify right side
    1,289.79x = 1,398,235.19
  5. Step 5: Solve for x
    x = 1,398,235.19/1,289.79
  6. Step 6: Final answer
    x = 1,084.08

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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.