Home / 1,285.75-1,774.38-820

Finding the Fourth Proportional to 1,285.75, 1,774.38 and 820

Calculator

Solution

The fourth proportional to 1,285.75, 1,774.38 and 820 is: 1,131.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285.75 : 1,774.38 = 820 : x
  2. Step 2: Convert to fraction form
    1,285.75/1,774.38 = 820/x
  3. Step 3: Cross multiply
    1,285.75x = 1,774.38 × 820
  4. Step 4: Simplify right side
    1,285.75x = 1,454,991.60
  5. Step 5: Solve for x
    x = 1,454,991.60/1,285.75
  6. Step 6: Final answer
    x = 1,131.63

Related Problems

Find fourth proportional to 642.88, 887.19 and 410
Half scale
Find fourth proportional to 2,571.50, 3,548.76 and 1,640
Double scale
Find fourth proportional to 1,286.75, 1,775.76 and 821
Similar ratio
Find fourth proportional to 1,928.63, 2,661.57 and 1,230
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.