The length of the base is 12 cm, and the height of the isosceles triangle on the base is 8 cm___ Cm.)

The length of the base is 12 cm, and the height of the isosceles triangle on the base is 8 cm___ Cm.)

According to the combination of three lines, the height of the bottom edge of an isosceles triangle is equal to the middle line of the bottom edge,
So half of the bottom is 12 / 2 = 6cm
And because it's 8cm high and 8cm long
Half of the bottom and waist, to form a right triangle, and the waist is hypotenuse
According to Pythagorean theorem:
6^2+8^2=x^2
x=10cm…… That is waist length

As shown in the figure, the length of the bottom edge of the isosceles triangle ABC is 8cm and the length of the waist is 5cm. A moving point P moves at a speed of 0.25mgs from B to C on the bottom edge. When the point P moves to the position where PA is perpendicular to the waist, the movement time of point P is calculated

As shown in the figure, make ad ⊥ BC, intersect BC at the point D, ∵ BC = 8cm, ∵ BD = CD = 12bc = 4cm, ∵ AB = 5cm, ∵ ad = 3cm, divided into two cases: when there is pa ⊥ AC after t second of point P movement, ∵ ap2 = Pd2 + ad2 = pc2-ac2, ∵ Pd2 + ad2 = pc2-ac2, ∵ Pd2 + 32 = (PD + 4) 2-52, ∵ PD = 2.25cm, ∵ BP = 4-2.25 = 1.75 = 0.25t, ∵ t = 7; t = 7sec, when there is pa ⊥ AB after t second of point P movement, we can prove that PD = 2.25,