Question

Triangle ABC had a perimeter 18 cm

Answer 1

Step-by-step explanation:

what is the main condition the lengths of the sides of a right-angled triangle have to fulfill ?

Pythagoras !

c² = a² + b²

c is the Hypotenuse (the baseline opposite of the 90 degree angle), a and b are the so-called legs (the sides enclosing the 90 degree angle).

only if there is a combination of the sides, for which the Pythagoras equation is true, do we have a right-angled triangle. otherwise not.

we also know CA = 18 - 7 - 3 = 8 cm

so, let's try

8² = 7² + 3²

64 = 49 + 9 = 58 wrong

7² = 8² + 3²

49 = 64 + 9 = 73 wrong

3² = 8² + 7²

9 = 64 + 49 = 113 wrong

so, there is no combination, where the Pythagoras equation is true, so it is NOT a right-angled triangle.