Home / 539.80-809.70-430.45

Finding the Fourth Proportional to 539.80, 809.70 and 430.45

Calculator

Solution

The fourth proportional to 539.80, 809.70 and 430.45 is: 645.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    539.80 : 809.70 = 430.45 : x
  2. Step 2: Convert to fraction form
    539.80/809.70 = 430.45/x
  3. Step 3: Cross multiply
    539.80x = 809.70 × 430.45
  4. Step 4: Simplify right side
    539.80x = 348,535.37
  5. Step 5: Solve for x
    x = 348,535.37/539.80
  6. Step 6: Final answer
    x = 645.68

Related Problems

Find fourth proportional to 269.90, 404.85 and 215.23
Half scale
Find fourth proportional to 1,079.60, 1,619.40 and 860.90
Double scale
Find fourth proportional to 540.80, 811.20 and 431.45
Similar ratio
Find fourth proportional to 809.70, 1,214.55 and 645.68
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.