In △ ABC, ∠ C = 60 °, BC = a, AC = B, AC + BC = 8, write the functional relationship between the area s and side length a of △ ABC and the value range of independent variable a

In △ ABC, ∠ C = 60 °, BC = a, AC = B, AC + BC = 8, write the functional relationship between the area s and side length a of △ ABC and the value range of independent variable a

Ad ⊥ BC over a to D (or D on the extension line of BC)
∵ ∠C=60°,
∴ ∠CAD=30°
∴ CD=1/2·AC=b/2
｜ ad = root (AC ^ 2-CD ^ 2) = root 3 / 2 · B
S △ = BC · AD / 2 = radical 3 / 4 · AB = radical 3 / 4 · a · (8-A)
Of which: 0

The perimeter of a triangular vegetable field is 108 meters, and the length ratio of the three sides is 3:4:5. How many meters is the longest side?

【108÷（3+4+5）】×5
=9×5
=45

In a triangular vegetable field, the length ratio of the three sides is 3:4:5, and the perimeter is 168 meters. What is the longest side?
My answer is 90, why 60?

Let X
3x+4x+5x=168
12x=168
x=14
Longest: 5x = 5 * 14 = 70
Your answer is wrong
I'm the original 1L. Is LS 60? Is it better than law?

A right triangle whose hypotenuse is 20 cm, and the difference between the two right sides is 4 cm, how many square centimeters is the area of this right triangle?
Yes, thank you!

Let one right edge be x and the other right edge be x + 4
According to Pythagorean theorem,
x²+(x+4)²=20²
x²+x²+8x+16=400
x²+4x-192=0
(x-12)(x+16)=0
X = 12, x = - 16 (rounding off)
the measure of area:
12×(12+4)÷2=96

If the three sides of a right triangle are 3 decimeters, 4 decimeters and 2 decimeters, then its area is (?)

According to the inverse theorem of Pythagorean theorem, it is not a right triangle, 3 ^ 2 + 2 ^ 2 = 13,4 ^ 2 = 16, it is not a special triangle. If 2 decimeter is changed to 5 decimeter, then 3 * 4 / 2 = 6 square decimeter. The area can be calculated by Helen's formula. Let a = 3, B = 4, C = 2, P = (a + B + C) / 2 = 9 / 2, △ ABC = √ P (P-A) (P-B) (P-C) = √ (9 / 2) (3 / 2) (1 / 2) (5

The three sides of a right triangle are 6 decimeters, 8 decimeters and 10 decimeters long respectively. Its area is () square decimeters
A. 48B. 40C. 30D. 24

The two right angle sides are 6 decimeters and 8 decimeters respectively, and the area of triangle is 6 × 8 △ 2 = 24 (square decimeters)

In △ ABC, ∠ B = 120 °, AC = 7, ab = 5, then the area of △ ABC is______ ．

From the cosine theorem, we can know that CoSb = 25 + BC2 − 492 · BC · 5 = - 12, and the area of BC = - 8 or 3 (rounding off) ∧ ABC is 12 · ab · BC · SINB = 12 × 5 × 3 × 32 = 1534, so the answer is: 1534

In triangle ABC, if AB = 3, BC = 5, AC = 7, then the area of triangle ABC is

(Helen formula) (P = (a + B + C) / 2) s = sqrt [P (P-A) (P-B) (P-C)]
p=7.5
S is about 6.495

In △ ABC, ∠ B = 120 °, AC = 7, ab = 5, then the area of △ ABC is______ ．

From the cosine theorem, we can know that CoSb = 25 + BC2 − 492 · BC · 5 = - 12, and the area of BC = - 8 or 3 (rounding off) ∧ ABC is 12 · ab · BC · SINB = 12 × 5 × 3 × 32 = 1534, so the answer is: 1534

In triangle ABC, B = 120 °, ab = 5, AC = 7, find the area of triangle ABC

According to a / Sina = B / SINB, we can know
AC / sin120 degree = AB / sinc
The degree of angle c can be calculated
And then according to the sum of the internal angles of the triangle is 180 degrees
Calculate the degree of angle A
According to the area of triangle s = 1 / 2Ab * ac * Sina