Home / 1,221.80-1,684.74-779

Finding the Fourth Proportional to 1,221.80, 1,684.74 and 779

Calculator

Solution

The fourth proportional to 1,221.80, 1,684.74 and 779 is: 1,074.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.80 : 1,684.74 = 779 : x
  2. Step 2: Convert to fraction form
    1,221.80/1,684.74 = 779/x
  3. Step 3: Cross multiply
    1,221.80x = 1,684.74 × 779
  4. Step 4: Simplify right side
    1,221.80x = 1,312,412.46
  5. Step 5: Solve for x
    x = 1,312,412.46/1,221.80
  6. Step 6: Final answer
    x = 1,074.16

Related Problems

Find fourth proportional to 610.90, 842.37 and 389.50
Half scale
Find fourth proportional to 2,443.60, 3,369.48 and 1,558
Double scale
Find fourth proportional to 1,222.80, 1,686.12 and 780
Similar ratio
Find fourth proportional to 1,832.70, 2,527.11 and 1,168.50
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.