Answer:
20 cm
Step-by-step explanation:
Pythagoras theorem states that a² + b² = c². But what does this actually mean? First of all we need to recognise that it only works in right-angled triangle. If I put the values in you would a² + 15² = 25². So we have to solve for "a". A = DC
a² + 15² = 25²
→ Minus 15² from both sides to isolate a²
a² = 25² - 15²
→ Work out 25² - 15²
a² = 400
→ Square root both sides to isolate a
a = 20
