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Xiao Ming uses a piece of rectangular cardboard 50cm in length and 40cm in width to make a cuboid box without cover. How to make the box the largest!
(50-10)X(40-10)X10=12000
1. The sum of all internal angles and an external angle of a polygon is 1340 degrees. Find the number of sides of the polygon and the degree of the external angle
2. In the triangle ABC, the angle B = angle c, the point E is on the extension line of Ca, and the angle AEF = angle
(picture: see question 2)
3. Read and understand: "in a triangle, if the angles are equal, then their opposite sides are also equal." for short, "equal angles to equal sides." as shown in Figure 3: in the triangle ABC, we know that the bisector of angle ABC and angle ACB intersects at point I, and the parallel line of angle BC crosses AB and AC at points D and e respectively. Please explain de = BD + CE with the knowledge of "equal angles to equal sides"
4. As shown in the figure: in the triangle ABC, the angle BAC = 120 degrees, ab = AC, ED and gf are the vertical bisectors of AB and AC respectively, the points E and G are on BC, BC = 145cn, find the length of eg
I have been on sick leave for a week because I am ill
Sorry, the second question is wrong
2. In the triangle ABC, the angle B = angle c, the point E is on the extension line of Ca, and the angle AEF = angle AFE, judge the position relationship between the straight line EF and BC, and explain the reason
(picture: see question 2)
I'm not sure about the second question. Please correct me
The relationship is vertical, and the method of proof is to make a parallel line of EF from a to BC, intersecting BC with D
So AFE = bad, AEF = CAD
Because AEF = AFE, bad = CAD
Because angle B = C, ad is the vertical bisector of triangle ABC
So ad is perpendicular to BC
Because ad is parallel to ef
So EF is perpendicular to BC
Question 1: 9-sided shape with 80 degrees outside angle
The third question
Because de / BC,
So DIB = IBC, EIC = ICB
Because DBI = IBC, ICB = ice
So DIB = DBI, ice = EIC
So DB = Di, ie = EC
So de = DB + EC
Question 4 eg = 145 / 3
1. When x = 1 / 4, the value of the power of the polynomial 2x-5x + the power of X + the power of 4x-3x-2 is?
2. If a + B = 3, ab = - 2, then (4a-5b-3ab) - (3a-6b + AB) =?
3. If the fifth power of polynomial X - (a + 2) the fourth power of X + the power of 7x + (B-3) X-9 does not contain the fourth power of X and the term of X, find the value of a + B
4. If the monomial y of 2mx to the power of a and y of - 5nx to the power of 2a-3 are monomials of X and y, and they are of the same kind
(1) Find the value of (7a-22) to the power of 2008
(2) If the power a of 2mx is y-5nx and the power 2a-3 of y-5nx is y = 0, and XY is not equal to 0, the power 2009 of (2m-5n) is obtained
I can't understand what you write
(2) First remove the brackets, expand your polynomial, simplify to get a + b-4ab, and then substitute it into the result = 11
(3) I don't know what you wrote
(4) It's too long. I don't want to see it. I'm sorry
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