Primary 3 Question Three sides of a triangle 27 35 54, find the area

Child, the knowledge of primary school can't be solved, you need to use the cosine theorem of high school, let me talk about the idea:

According to the length of the three sides, find the cosine of any angle (cosine theorem).

Then find the area (s=.) according to the sinusoidal of the angle to be sought

Is it a 3rd grade question? It could be 378, huh.

This elementary school student can't do it, but what kind of triangle is this?

Elementary school wouldn't be so miserable.

Uh......Draw your own drawings and do the math.

The three sides of the triangle are 60, 87, and 43, and the area is found.

The three sides of the triangle a, b, and c are known, and when the area of the triangle is found, the formula can be used: stove leakage.

Area [s(s-a)(s-b)(s-c)], where s=(a+b+c) 2, in this question s (60+87+43) 2 95

So the area of the three ants argues that the angle is d [95(95-60)(95-87)(95-43)] 1383200

Method 1: The three sides of the triangle are 60,87 and 43, and the half circumference p = 95

By Helen Split formula s = p(p-a)(p-b)(p-c)] 95x35x8x52] =

Method 2: 43 2 = 60 2 + 87 2 - 2 x 60 x 87 cosc

cosc = , sinc =

s = 1/2) x 60 x 87 x =

The formula for finding the area of a triangle directly by using the side lengths of the three sides of a triangle. (a, b, and c are the side lengths of the three sides of the triangle, respectively, and p is half the circumference of the triangle).

For this question, p= (34+

So the area is:

The area of the triangle is base times height 2.

You can use the cosine theorem to do this problem, find the cosine value of any angle according to the three edges, and then find the corresponding sine value, and then use the sine theorem to find the area!

But it is also possible to use the "Helen Area Formula."

There's not much more to say! Just use it! Because this formula is recognized! As long as you know how to use! No one dares to say that you are wrong!

s=√[p(p-a)(p-b)(p-c)]=√[

approx. equivalent).