Home / 447.20-670.80-387.20

Finding the Fourth Proportional to 447.20, 670.80 and 387.20

Calculator

Solution

The fourth proportional to 447.20, 670.80 and 387.20 is: 580.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    447.20 : 670.80 = 387.20 : x
  2. Step 2: Convert to fraction form
    447.20/670.80 = 387.20/x
  3. Step 3: Cross multiply
    447.20x = 670.80 × 387.20
  4. Step 4: Simplify right side
    447.20x = 259,733.76
  5. Step 5: Solve for x
    x = 259,733.76/447.20
  6. Step 6: Final answer
    x = 580.80

Related Problems

Find fourth proportional to 223.60, 335.40 and 193.60
Half scale
Find fourth proportional to 894.40, 1,341.60 and 774.40
Double scale
Find fourth proportional to 448.20, 672.30 and 388.20
Similar ratio
Find fourth proportional to 670.80, 1,006.20 and 580.80
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.