Home / 445.20-667.80-385.80

Finding the Fourth Proportional to 445.20, 667.80 and 385.80

Calculator

Solution

The fourth proportional to 445.20, 667.80 and 385.80 is: 578.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    445.20 : 667.80 = 385.80 : x
  2. Step 2: Convert to fraction form
    445.20/667.80 = 385.80/x
  3. Step 3: Cross multiply
    445.20x = 667.80 × 385.80
  4. Step 4: Simplify right side
    445.20x = 257,637.24
  5. Step 5: Solve for x
    x = 257,637.24/445.20
  6. Step 6: Final answer
    x = 578.70

Related Problems

Find fourth proportional to 222.60, 333.90 and 192.90
Half scale
Find fourth proportional to 890.40, 1,335.60 and 771.60
Double scale
Find fourth proportional to 446.20, 669.30 and 386.80
Similar ratio
Find fourth proportional to 667.80, 1,001.70 and 578.70
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.