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Finding the Fourth Proportional to 1,378.75, 1,904.30 and 912.19

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Solution

The fourth proportional to 1,378.75, 1,904.30 and 912.19 is: 1,259.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.75 : 1,904.30 = 912.19 : x
  2. Step 2: Convert to fraction form
    1,378.75/1,904.30 = 912.19/x
  3. Step 3: Cross multiply
    1,378.75x = 1,904.30 × 912.19
  4. Step 4: Simplify right side
    1,378.75x = 1,737,083.42
  5. Step 5: Solve for x
    x = 1,737,083.42/1,378.75
  6. Step 6: Final answer
    x = 1,259.90

Related Problems

Find fourth proportional to 689.38, 952.15 and 456.10
Half scale
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Double scale
Find fourth proportional to 1,379.75, 1,905.68 and 913.19
Similar ratio
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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.