1. **Problem statement:** Given an isosceles triangle $\triangle ABC$ with $|AB|=|AC|=6$ cm and $|BC|=4$ cm, find the points equidistant from $B$ and $C$ and 3 cm from $A$, then measure their distance from line $BC$.
2. **Key concepts and formulas:**
- The locus of points equidistant from $B$ and $C$ is the perpendicular bisector of segment $BC$.
- The locus of points 3 cm from $A$ is a circle centered at $A$ with radius 3 cm.
- The intersection of these two loci gives the points satisfying both conditions.
3. **Step-by-step solution:**
1. Calculate the midpoint $M$ of $BC$:
$$M = \left(\frac{B_x + C_x}{2}, \frac{B_y + C_y}{2}\right)$$
Since $|BC|=4$ cm, place $B$ at $(0,0)$ and $C$ at $(4,0)$ for convenience, so
$$M = (2,0)$$
2. The perpendicular bisector of $BC$ is the vertical line through $M$:
$$x=2$$
3. The circle centered at $A$ with radius 3 cm:
Since $|AB|=6$ and $|AC|=6$, $A$ lies on the perpendicular bisector of $BC$ at a height $h$ such that
$$AB^2 = AM^2 + BM^2 \Rightarrow 6^2 = h^2 + 2^2 \Rightarrow 36 = h^2 + 4 \Rightarrow h^2 = 32 \Rightarrow h = 4\sqrt{2}$$
So $A = (2, 4\sqrt{2})$.
4. Equation of the circle:
$$ (x-2)^2 + (y - 4\sqrt{2})^2 = 3^2 = 9 $$
5. Find intersection points of the circle and line $x=2$:
Substitute $x=2$ into the circle equation:
$$ (2-2)^2 + (y - 4\sqrt{2})^2 = 9 \Rightarrow (y - 4\sqrt{2})^2 = 9 $$
6. Solve for $y$:
$$ y - 4\sqrt{2} = \pm 3 \Rightarrow y = 4\sqrt{2} \pm 3 $$
7. The two points are:
$$ P_1 = (2, 4\sqrt{2} + 3), \quad P_2 = (2, 4\sqrt{2} - 3) $$
8. Distance from $BC$ (the $x$-axis) is the absolute $y$-coordinate:
$$ d_1 = 4\sqrt{2} + 3, \quad d_2 = 4\sqrt{2} - 3 $$
**Final answer:** The points equidistant from $B$ and $C$ and 3 cm from $A$ lie on $x=2$ at heights $4\sqrt{2} \pm 3$ cm, and their distances from $BC$ are $4\sqrt{2} + 3$ cm and $4\sqrt{2} - 3$ cm respectively.
Isosceles Triangle Locus 2Ba735
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.