Home / 643.80-965.40-278.40

Finding the Fourth Proportional to 643.80, 965.40 and 278.40

Calculator

Solution

The fourth proportional to 643.80, 965.40 and 278.40 is: 417.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 965.40 = 278.40 : x
  2. Step 2: Convert to fraction form
    643.80/965.40 = 278.40/x
  3. Step 3: Cross multiply
    643.80x = 965.40 × 278.40
  4. Step 4: Simplify right side
    643.80x = 268,767.36
  5. Step 5: Solve for x
    x = 268,767.36/643.80
  6. Step 6: Final answer
    x = 417.47

Related Problems

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.