(There must be a neat geometric argument for this, but if we take vectors origin B, then BX=BN/2=BA/4+BC/4, so BZ=BA/3 and so XZ=1/3(BA//A-3BC/4)=CX/3.) So now triangles BXC and ZXG are similar, so ZG is parallel to BC, so Z is B' and X is C''. But A'...
To solve the problem, we need to find the perimeter of triangle ABC given the relation r1+r2=r3−r, where r1,r2,r3, and r are defined in terms of the area and semi-perimeter of the triangle. 1. Understanding the Variables: - Let a,b,c be the sides of triangle ABC. - The s...
结果1 题目 In a triangle ABC, is true relationship c is less than b, and b is less than a. Internal angles of the triangle are in the ratio 5:4:9. The size of the internal angle bet a is: 相关知识点: 试题来源: 解析 x=(180)/(5+4+9)=10° ⊙ 反馈 收藏 ...
A B C D is a parallelogram. P is a point on A D such that A P=1/3A D a... 01:24 In a A B C ,\ B M\ a n d\ C N are perpendiculars from B\ a n d\ C r... 01:37 In triangle ABC, M ,N and P are the mid-points of A B ,A C and B C res... 02:19 ...
百度试题 结果1 题目(C)3. A and a rectangle make a tree. A. square B. triangle C. circle 相关知识点: 试题来源: 解析 答案见上 反馈 收藏
define ISTRIANGLE(a,b,c) a+b>c && a+c>b && b+c>a define AREA(a,b,c) sqrt(S(a,b,c)*(S(a,b,c)-a)*(S(a,b,c)-b)*(S(a,b,c)-c))define S(a,b,c) (a+b+c)/2 在使用宏之前建议加一个判断条件 if((a>(b+c))||(b>(a+c))||(c>(a+b))){ pri...
解:由正弦定理可知 \dfrac {a}{\sin A}= \dfrac {b}{\sin B}⇒ \dfrac {a}{b}= \dfrac {\sin A}{\sin B}, ∵\triangle ABC中,∠A,∠B,∠C均小于180^{\circ},角A、B、C所对应的边分别为a,b,c, ∴a,b,\sin A,\sin B都是正数, ∴“a\leqslant b”⇔“\sin A\leqslant \s...
若一个三角形的三边a，b，c （ ） 满足：1、 ，则这个三角形是锐角三角形；2、 ，则这个三角形是直角三角形；3、 ，则这个三角形是钝角三角形。按边分 1、不等边三角形；不等边三角形，数学定义，指的是三条边都不相等的三角形叫不等边三角形。2、等腰三角形；等腰三角形（isosceles triangle），指两边...
In a triangle ABC, the points D, E and F are the midpoints of AB, BC and CA respectively. Point P lies in the plane of the triangle. By setting , and , show that . 答案 so Similarly and Hence 相关推荐 1In a triangle ABC, the points D, E and F are the midpoints of...
解:\cos B= \dfrac {a^{2}+c^{2}-b^{2}}{2ac}= \dfrac {a^{2}+c^{2}-( \dfrac {a+c}{2})^{2}}{2ac}= \dfrac {3a^{2}+3c^{2}-2ac}{8ac}\geqslant \dfrac {6ac-2ac}{8ac}= \dfrac {1}{2}, 当且仅当a=c=b,即\triangle ABC为等边三角形时,\cos B= \d...