Home / 676.80-1,015.20-385.20

Finding the Fourth Proportional to 676.80, 1,015.20 and 385.20

Calculator

Solution

The fourth proportional to 676.80, 1,015.20 and 385.20 is: 577.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    676.80 : 1,015.20 = 385.20 : x
  2. Step 2: Convert to fraction form
    676.80/1,015.20 = 385.20/x
  3. Step 3: Cross multiply
    676.80x = 1,015.20 × 385.20
  4. Step 4: Simplify right side
    676.80x = 391,055.04
  5. Step 5: Solve for x
    x = 391,055.04/676.80
  6. Step 6: Final answer
    x = 577.80

Related Problems

Find fourth proportional to 338.40, 507.60 and 192.60
Half scale
Find fourth proportional to 1,353.60, 2,030.40 and 770.40
Double scale
Find fourth proportional to 677.80, 1,016.70 and 386.20
Similar ratio
Find fourth proportional to 1,015.20, 1,522.80 and 577.80
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.