An obtuse triangle, 150 degrees top angle, 20 cm on both sides, 30 cm area

An obtuse triangle, 150 degrees top angle, 20 cm on both sides, 30 cm area

S△=1/2*absinC
=1/2*20*30*sin150
=150 square centimeter

In the obtuse angle triangle, the obtuse angle is 150 degrees, the length of one side is √ 3, and the length of one side is 1 We need the process, the results

Let ∠ a = 150 ° in △ ABC, ab = √ 3, AC = 1, and the longest side is BC, then ∠ bad = 30 ° in RT △ ADB, ∠ bad = 30 ° and ab = √ 3, then BD = √ 3 / 2, ad = 3 / 2, RT △ CDB, CD = AC + ad = 1 + 3 / 2 = 5 / 2

Given that the length of the three sides of an obtuse triangle is 2,3,4, calculate the area of the triangle It's better to have a picture,

Make the height on the longest side, and let it divide the bottom edge into two parts: X and 4-x. according to Pythagorean theorem, there are
　　3²-x²=2²-（4-x）²
X = 21 / 8
Therefore, the height on the longest side = √ (9-441 / 64) = 3 √ 15 / 8
Therefore, the area of the triangle is 1 / 2 × 4 × 3 √ 15 / 8 = 3 √ 15 / 4

How to draw an obtuse triangle with an area of 3 on a grid paper

On the grid paper, draw the bottom ab of the triangle. You can draw three unit length. Then draw the extension line BC of the AB line segment (note that it is a dotted line), draw a length, and then make a height CD from point C upward, draw two units (note that it is also a dotted line, because the height of AB side of the obtuse triangle is outside the triangle), and then connect AD and BD respectively. The area is 3

The side length of each small square in the checkerboard paper is 1 unit. Make an obtuse triangle to make the area 3 and calculate the length of the three sides

According to the Pythagorean theorem, the three sides are 1, √ 10, √ 13

Make an obtuse triangle with an area of 3 and find the length of three sides It's in square paper with one unit of side length

Impossible, the square of area 1 makes the triangle of area 3!

As shown in Fig. 4 * 4, make an obtuse triangle so that the area is 65 below the root and divided by 2

Make a triangle with root 5 and root 13
The side of Radix 5 can be made with the hypotenuse of a right triangle with side lengths of 1 and 2
The side of root 13 can be made with the hypotenuse of a right triangle with side lengths of 2 and 3

How to calculate the area of an obtuse triangle? If the longest side is not used to calculate the base, how should the base and height be obtained? (to be illustrated)

The height is obtained by making a vertical line from the apex of acute angle to the extension line of the edge with obtuse angle
That side is lengthened, he's the bottom, and the vertical is the height

Find the area of obtuse triangle Take the three sides of triangle a as the side length and make three squares outwards. The areas of the three squares are 370, 116 and 74 respectively. What is the area of triangle a

From the square area, we can set the three sides of △ ABC AB = √ 370, AC = √ 74, CB = √ 116,
The vertical line of AB is drawn through point C, and the vertical foot is point D,
If ad = x, then BD = √ 370-x,
According to Pythagorean theorem, AC 2 - Ad 2 = CD 2 = CB 2 - BD 2, then:
74－x²=116－﹙√370－x﹚²,
The solution is: x = 164 / √ 370,
∴CD=22／√370,
The area of △ ABC = Δ ab × CD
=½×√370×22／√370
=11

What is the formula of permutation and combination in mathematics? I learned it in high school, but I've forgotten, High school basic formula is OK!

pmn=m!/(m-n)!
cmn=pmn/n!