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If the circumference of the isosceles △ ABC is 10 cm, the bottom edge length is y cm, and the waist length is x cm, then the value range of waist length x is______ .
According to known, y = 10-2x
According to the trilateral relationship of the triangle, the
10−2x＞0
2x＞10−2x ，
5 ＜ x ＜ 5
Therefore, X ＜ 5
The circumference of isosceles triangle is 10 cm, the length of base BC is YCM, and the length of waist AB is xcm (1) Write the function relation of Y with respect to X; (2) Find the value range of X; (3) Find the value range of Y
（1）y=10-2x；
（2）∵x＞0，y＞0，2x＞y∴10-2x＞0，2x＞10-2x，
The solution is 5
2＜x＜5；
（3）∵x=5-y
2∴5
2＜5-y
2＜5，
The solution is 0 ＜ y ＜ 5
If the waist ab of isosceles △ ABC is 10cm long and 32cm girth, then the height of AB edge is______ cm．
∵ isosceles ᙽ the waist of △ ABC is 10cm in length and 32cm in circumference, ᙽ AB = AC = 10cm, bottom length BC = 32cm-10cm-10cm = 12cm. ∵ ad is the height above the bottom edge,
The base edge BC of the isosceles triangle ABC is 16 cm and the waist length is ab = 10 cm. A moving point P moves from point B to point C at a speed of 0.5 cm / s. when point P moves to the vertical position of PA and waist, then the telecontrol time of point P is__________ Seconds
(Peng duanshu)
As shown in the figure, we know that the base edge BC of isosceles △ ABC is 10cm, D is a point on waist AB, and CD = 8cm, BD = 6cm. Find the circumference of △ ABC
Let AB = X
∵BC=10cm，CD=8cm，BD=6cm
BC2 = BD2 + CD2 BDC is a right triangle
∵ isosceles △ ABC
∴AB=AC=x
∵AC2=AD2+CD2
x2=（x-6）2+82
∴x=25
Three
The circumference of △ ABC = 2Ab + BC = 80
3．
It is known that ab = 12, ab = 10
∵ ad is the midline of ᙽ ABC, BC = 10,
∴BD=DC=1
2BC=5．
∵BD2+AD2=52+122=132=AB2，
∴AD⊥BC，
∵ ad is the center line of BC side of ᙽ ABC,
The ad is the vertical line of BC,
∴AB=AC．
It is known that in △ ABC, ab = 13cm, BC = 10cm, midline on BC edge, ad = 12cm,
What exactly are you asking? Is it a proof question? Is it the length of BC
As shown in the figure, in △ ABC, ab = AC = 10cm, BC = 12cm, ad is the middle line of △ ABC, e and F are two points on ad, then the area of shadow is______ cm2．
∵ AB = AC = 10cm, BC = 12cm, ad is the center line of △ ABC,
It is known that ab = 12, ab = 10
∵ ad is the midline of ᙽ ABC, BC = 10,
∴BD=DC=1
2BC=5．
∵BD2+AD2=52+122=132=AB2，
∴AD⊥BC，
∵ ad is the center line of BC side of ᙽ ABC,
The ad is the vertical line of BC,
∴AB=AC．
It is known that ab = 12, ab = 10
∵ ad is the midline of ᙽ ABC, BC = 10,
∴BD=DC=1
2BC=5．
∵BD2+AD2=52+122=132=AB2，
∴AD⊥BC，
∵ ad is the center line of BC side of ᙽ ABC,
The ad is the vertical line of BC,
∴AB=AC．
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