Home / 928.16-1,390.94-721.80

Finding the Fourth Proportional to 928.16, 1,390.94 and 721.80

Calculator

Solution

The fourth proportional to 928.16, 1,390.94 and 721.80 is: 1,081.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.16 : 1,390.94 = 721.80 : x
  2. Step 2: Convert to fraction form
    928.16/1,390.94 = 721.80/x
  3. Step 3: Cross multiply
    928.16x = 1,390.94 × 721.80
  4. Step 4: Simplify right side
    928.16x = 1,003,980.49
  5. Step 5: Solve for x
    x = 1,003,980.49/928.16
  6. Step 6: Final answer
    x = 1,081.69

Related Problems

Find fourth proportional to 464.08, 695.47 and 360.90
Half scale
Find fourth proportional to 1,856.32, 2,781.88 and 1,443.60
Double scale
Find fourth proportional to 929.16, 1,392.44 and 722.80
Similar ratio
Find fourth proportional to 1,392.24, 2,086.41 and 1,082.70
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.