Home / 1,079.20-1,620-430.39

Finding the Fourth Proportional to 1,079.20, 1,620 and 430.39

Calculator

Solution

The fourth proportional to 1,079.20, 1,620 and 430.39 is: 646.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.20 : 1,620 = 430.39 : x
  2. Step 2: Convert to fraction form
    1,079.20/1,620 = 430.39/x
  3. Step 3: Cross multiply
    1,079.20x = 1,620 × 430.39
  4. Step 4: Simplify right side
    1,079.20x = 697,231.80
  5. Step 5: Solve for x
    x = 697,231.80/1,079.20
  6. Step 6: Final answer
    x = 646.06

Related Problems

Find fourth proportional to 539.60, 810 and 215.20
Half scale
Find fourth proportional to 2,158.40, 3,240 and 860.78
Double scale
Find fourth proportional to 1,080.20, 1,621.50 and 431.39
Similar ratio
Find fourth proportional to 1,618.80, 2,430 and 645.59
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.