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The base length of isosceles triangle is 20cm. The middle line on one waist divides the circumference of triangle into two parts, one part is 8cm longer than the other part
The center line divides the triangle into two parts, the length of which is
Waist length + waist length / 2 and bottom side length + waist length / 2
1：
Waist length + waist length / 2 - (bottom edge length + waist length / 2) = 8
Waist length = base length + 8 = 20 + 8 = 28cm
2:
Bottom length + waist length / 2 - (waist length + waist length / 2) = 8
Waist length = base length - 8 = 20 - 8 = 12 cm
A: the waist length is 28 cm or 12 cm
The median line on the waist of an isosceles triangle divides the circumference of the triangle into two parts: 20cm and 36cm, and calculates the length of each side of the triangle
Let the waist length be x and the base length y
X + X / 2 = 20, y + X / 2 = 36; or x + X / 2 = 36, y + X / 2 = 20
X = 40 / 3, y = 88 / 3; or x = 24, y = 8
The length of three sides is 40 / 3,40 / 3,88 / 3; or the length of three sides is 24,24,8
If the circumference of the isosceles triangle is 20 cm and the height on the bottom is 6 cm, then the length of the base is___ cm．
Let the waist length be x and the base length be 2Y,
Then 2x + 2Y = 20, 62 + y2 = x2,
The solution is y = 3.2,
So 2Y = 6.4 (CM)
So the answer is: 6.4
If the circumference of the isosceles triangle is 20 cm and the height on the bottom is 6 cm, then the length of the base is___ cm．
Let the waist length be x and the base length be 2Y,
Then 2x + 2Y = 20, 62 + y2 = x2,
The solution is y = 3.2,
So 2Y = 6.4 (CM)
So the answer is: 6.4
It is known that the circumference of isosceles triangle is 40cm, and the length of one side is 1 / 2 of the waist length
The length of one side is half of the waist length
This side must be the bottom edge, and each waist is twice the bottom edge
therefore
The circumference of a triangle is five times the base
therefore
Bottom edge = 40 △ 5 = 8 (CM)
Waist = 8 × 2 = 16 (CM)
In isosceles △ ABC, the median line BD on one waist AC divides the circumference of △ ABC into two parts of 12cm and 15cm, and calculates the lengths of each side of △ ABC
As shown in the figure, ∵ BD is the center line,
When 12cm is the sum of waist length and half of waist length, waist length = 12 △ 1.5 = 8cm,
Bottom edge = 15-8 × 1
2=11cm，
The three sides of the triangle are 8cm, 8cm and 11cm respectively,
It can form triangles,
When 15cm is the sum of waist length and half of waist length, waist length = 15 △ 1.5 = 10cm,
Bottom edge = 12 × 1
2=7cm，
The three sides of the triangle are 10cm, 10cm and 7cm respectively,
It can form triangles,
In conclusion, the length of each side of △ ABC is 8cm, 8cm, 11cm or 10cm, 10cm, 7cm respectively
Given Tan α = 3, how many trigonometric functions is the planting of sin ^ 2 α - 3sin α cos α + 4cos ^ 2 α
sin^2 α-3sinαcosα+4cos^2 α=(sin^2 α-3sinαcosα+4cos^2 α)/(sin²α+cos²α)
=( tan^2 α-3tanα+4)/ (tan²α+1)=(9-3×3+4)/(9+1)=2/5.
Given that cos (75 degrees + a) = 5 △ 13a is the third quadrant angle, find the value of sin (195 degrees - a) + cos (A-15 degrees)
Cos (75 degrees + a) = 5 ￣ 13 = cos (285 degrees - a)
Sin (195 degrees - a) = cos (285 degrees - a) = 5 ÷ 13
Sin (195 degrees - a) + cos (A-15 degrees) = sin (195 degrees - a) + cos (15 degrees - a) = sin (195 degrees - a) - cos (195 degrees - a) = 5 △ 13
-12÷13=-7÷13
Given that cos (75 degrees + a) = 5 ￣ 13a is the third quadrant angle, find the value o of sin (195 degrees - a) + cos (A-15 degrees)
Cos (75 degrees + a) = 5 ￣ 13 = cos (285 degrees - a)
Sin (195 degrees - a) = cos (285 degrees - a) = 5 ÷ 13
Sin (195 degrees - a) + cos (A-15 degrees) = sin (195 degrees - a) + cos (15 degrees - a) = sin (195 degrees - a) - cos (195 degrees - a) = 5 △ 13
-12÷13=-7÷13
Given cos (75'a) = 5 /! 3, a is the third quadrant angle, find the value of sin (195 '- a) cos (A-15') My math idiot thinks it's very difficult. Big brother and sister teach me
Cos (75 degrees + a) = 5 ￣ 13 = cos (285 degrees - a) sin (195 degrees - a) = cos (285 degrees - a) = 5 ￣ 13 sin (195 degrees - a) + cos (A-15 degrees) = sin (195 degrees - a) + cos (15 degrees - a) = sin (195 degrees - a) - cos (195 degrees - a) = 5 ￣ 13 - 12 ￣ 13 = - 7 ￣ 13
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