Answer:
1. The values of |PQ|, |QR| and |RP| are 3, 3√5 and 6 respectively.
2. No.
3. No.
Explanation:
The vertices of given triangle are P(0, 1, 5), Q(2, 3, 4), R(2, −3, 1).
Distance formula:
![D=√((x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2)](https://img.qammunity.org/2020/formulas/mathematics/college/ir3uxzyam2uupy4o62jx4ew4oa0nk9626l.png)
Using distance formula we get
![|PQ|=√((2-0)^2+(3-1)^2+(4-5)^2)=√(9)=3](https://img.qammunity.org/2020/formulas/mathematics/college/6e9fcholciyzf285uerdquejzdwxsebobd.png)
![|QR|=√((2-2)^2+(-3-3)^2+(1-4)^2)=√(45)=3√(5)](https://img.qammunity.org/2020/formulas/mathematics/college/j4a5mo1c2e9r8t5rh9vlkqye0lyfpwinsb.png)
![|RP|=√((0-2)^2+(1-(-3))^2+(5-1)^2)=√(36)=6](https://img.qammunity.org/2020/formulas/mathematics/college/vhcp2y2n6z99hjizeoc67ouz3207jyz6rf.png)
The values of |PQ|, |QR| and |RP| are 3, 3√5 and 6 respectively.
In a right angled triangle the sum of squares of two small sides is equal to the square of third side.
![(3)^2+(3√(5))^2=54\\eq 6^2](https://img.qammunity.org/2020/formulas/mathematics/college/nes6pduwpht779w1nmxii6j0dcwvab1g94.png)
Therefore PQR is not a right angled triangle.
In an isosceles triangle, the length of two sides are equal.
The measure of all sides are different, therefore PQR is not an isosceles triangle.