All categories

4 years ago

My question is in the picture pls help

Mathematics

1 answer:

pentagon [3]4 years ago

8 0

Answer:

A. 8cm

Step-by-step explanation:

3 times 2 is 6. 22-6 is 16. 16/2 is 8

You might be interested in

Triangles Unit Test part 1 A length of rope is stretched between the top edge of a building and a stake in the ground. The head

musickatia [10]

Answer:

The building is 32 feet tall.

Step-by-step explanation:

Consider the figure drawn below representing the given scenario.

AB represents the height of building, BC is the distance between the stake and building, C represents the stake at ground level, and DE represents the height of the tree growing halfway between building and stake.

Since the tree is growing halfway between B and C, therefore, the point E divides the line segment BC into 2 equal parts.

Therefore, $BE = EC$ or E is the midpoint of BC.

Also, from the figure, it is clear that both tree and building are vertical to the ground. So, DE || AB.

Now, from converse of mid-segment theorem, if a line passes through the midpoint of one side of a triangle and also parallel to the third side, then the line also passes through the midpoint of the second side and half the length of the third side (parallel side)

So,

$DE=\frac{1}{2}\times AB\\\\16=\frac{AB}{2}\\\\AB=16\times 2=32\ ft$

Therefore, the building is 32 feet tall.

5 0

3 years ago

Please dont ignore, Need help!!! Use the law of sines/cosines to find..

Ket [755]

Answer:

16. Angle C is approximately 13.0 degrees.

17. The length of segment BC is approximately 45.0.

18. Angle B is approximately 26.0 degrees.

15. The length of segment DF "e" is approximately 12.9.

Step-by-step explanation:

By the law of sine, the sine of interior angles of a triangle are proportional to the length of the side opposite to that angle.

For triangle ABC:

$\sin{A} = \sin{103\textdegree{}}$ ,
The opposite side of angle A $a = BC = 26$ ,
The angle C is to be found, and
The length of the side opposite to angle C $c = AB = 6$ .

$\displaystyle \frac{\sin{C}}{\sin{A}} = \frac{c}{a}$ .

$\displaystyle \sin{C} = \frac{c}{a}\cdot \sin{A} = \frac{6}{26}\times \sin{103\textdegree}$ .

$\displaystyle C = \sin^{-1}{(\sin{C}}) = \sin^{-1}{\left(\frac{c}{a}\cdot \sin{A}\right)} = \sin^{-1}{\left(\frac{6}{26}\times \sin{103\textdegree}}\right)} = 13.0\textdegree{}$ .

Note that the inverse sine function here $\sin^{-1}()$ is also known as arcsin.

By the law of cosine,

$c^{2} = a^{2} + b^{2} - 2\;a\cdot b\cdot \cos{C}$ ,

where

$a$ , $b$ , and $c$ are the lengths of sides of triangle ABC, and
$\cos{C}$ is the cosine of angle C.

For triangle ABC:

$b = 21$ ,
$c = 30$ ,
The length of $a$ (segment BC) is to be found, and
The cosine of angle A is $\cos{123\textdegree}$ .

Therefore, replace C in the equation with A, and the law of cosine will become:

$a^{2} = b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}$ .

$\displaystyle \begin{aligned}a &= \sqrt{b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}}\\&=\sqrt{21^{2} + 30^{2} - 2\times 21\times 30 \times \cos{123\textdegree}}\\&=45.0 \end{aligned}$ .

For triangle ABC:

$a = 14$ ,
$b = 9$ ,
$c = 6$ , and
Angle B is to be found.

Start by finding the cosine of angle B. Apply the law of cosine.

$b^{2} = a^{2} + c^{2} - 2\;a\cdot c\cdot \cos{B}$ .

$\displaystyle \cos{B} = \frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}$ .

$\displaystyle B = \cos^{-1}{\left(\frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}\right)} = \cos^{-1}{\left(\frac{14^{2} + 6^{2} - 9^{2}}{2\times 14\times 6}\right)} = 26.0\textdegree$ .