Answer :
Distance between points P(a,b) and Q(c,d) is = √[ (a-c)²+(b-d)² ]
Find the lengths of the sides. If you find two sides are equal then it is an isosceles triangle. Let us say the first point is P, second Q and the third R
1. PQ = √[(-2-4)²+(0-0)²] = 6 QR = √[(4-1)²+(0-3)²] = √18
PR = √[(-2-1)² +(0-3)² ] = √18 PR = QR
2. PQ = √[(1+5)²+(-2-1)²] = √45 QR = √[(-5-1)²+(1-4)²] = √45
PQ = QR
3. PQ = √[(-1-2)²+(-3+1)²] = √13 QR = √[(2+1)²+(-1-1)²] = √13
PQ = QR
so isosceles Δ
Find the lengths of the sides. If you find two sides are equal then it is an isosceles triangle. Let us say the first point is P, second Q and the third R
1. PQ = √[(-2-4)²+(0-0)²] = 6 QR = √[(4-1)²+(0-3)²] = √18
PR = √[(-2-1)² +(0-3)² ] = √18 PR = QR
2. PQ = √[(1+5)²+(-2-1)²] = √45 QR = √[(-5-1)²+(1-4)²] = √45
PQ = QR
3. PQ = √[(-1-2)²+(-3+1)²] = √13 QR = √[(2+1)²+(-1-1)²] = √13
PQ = QR
so isosceles Δ