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4 years ago

There are eight pencils in a package. How many packages will be needed for 28 children if each child gets 4 pencils?

Mathematics

2 answers:

eduard4 years ago

6 0

14 packages
28(children) × 4(pencils) = 112(pencils)
112(pencils) ÷ 8(pencils per package) = 14(packages)

zimovet [89]4 years ago

3 0

Seven because 4x7 equals 28

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Looking at the top of tower A and base of tower B from points C and D, we find that ∠ACD = 60°, ∠ADC = 75° and ∠ADB = 30°. Let t

katrin2010 [14]

Answer:

$\text{Exact: }AB=25\sqrt{6},\\\text{Rounded: }AB\approx 61.24$

Step-by-step explanation:

We can use the Law of Sines to find segment AD, which happens to be a leg of $\triangle ACD$ and the hypotenuse of $\triangle ADB$ .

The Law of Sines states that the ratio of any angle of a triangle and its opposite side is maintained through the triangle:

$\frac{a}{\sin \alpha}=\frac{b}{\sin \beta}=\frac{c}{\sin \gamma}$

Since we're given the length of CD, we want to find the measure of the angle opposite to CD, which is $\angle CAD$ . The sum of the interior angles in a triangle is equal to 180 degrees. Thus, we have:

$\angle CAD+\angle ACD+\angle CDA=180^{\circ},\\\angle CAD+60^{\circ}+75^{\circ}=180^{\circ},\\\angle CAD=180^{\circ}-75^{\circ}-60^{\circ},\\\angle CAD=45^{\circ}$

Now use this value in the Law of Sines to find AD:

$\frac{AD}{\sin 60^{\circ}}=\frac{100}{\sin 45^{\circ}},\\\\AD=\sin 60^{\circ}\cdot \frac{100}{\sin 45^{\circ}}$

Recall that $\sin 45^{\circ}=\frac{\sqrt{2}}{2}$ and $\sin 60^{\circ}=\frac{\sqrt{3}}{2}$ :

$AD=\frac{\frac{\sqrt{3}}{2}\cdot 100}{\frac{\sqrt{2}}{2}},\\\\AD=\frac{50\sqrt{3}}{\frac{\sqrt{2}}{2}},\\\\AD=50\sqrt{3}\cdot \frac{2}{\sqrt{2}},\\\\AD=\frac{100\sqrt{3}}{\sqrt{2}}\cdot\frac{ \sqrt{2}}{\sqrt{2}}=\frac{100\sqrt{6}}{2}={50\sqrt{6}}$

Now that we have the length of AD, we can find the length of AB. The right triangle $\triangle ADB$ is a 30-60-90 triangle. In all 30-60-90 triangles, the side lengths are in the ratio $x:x\sqrt{3}:2x$ , where $x$ is the side opposite to the 30 degree angle and $2x$ is the length of the hypotenuse.

Since AD is the hypotenuse, it must represent $2x$ in this ratio and since AB is the side opposite to the 30 degree angle, it must represent $x$ in this ratio (Derive from basic trig for a right triangle and $\sin 30^{\circ}=\frac{1}{2}$ ).

Therefore, AB must be exactly half of AD:

$AB=\frac{1}{2}AD,\\AB=\frac{1}{2}\cdot 50\sqrt{6},\\AB=\frac{50\sqrt{6}}{2}=\boxed{25\sqrt{6}}\approx 61.24$

3 0

3 years ago

Read 2 more answers

Explain answer ! <br><br> Will give brainlst

Ne4ueva [31]

Answer:

x = 4, y = 2

Step-by-step explanation:

Start by multiplying the first equation by 2:

2x + 2y = 12 --> 4x + 4y = 24

Subtract the second from the first:

4x + 4y = 24

- 5x + 4y = 28

4x - 5x = -x

4y = 4y = 0

24 - 28 = -4

so you end with -x + 0 = -4

Solve for x to get x = 4

Plug x = 4 back into 2x + 2y = 12 to find y.

2(4) + 2y = 12

8 + 2y = 12

2y = 4

y = 2

5 0

3 years ago

A square has a length of 4.8 feet. If the square is dilated by a factor of 4 , what is the length of a side of the new square? W

oksano4ka [1.4K]

Answer:

4.8x4=19.2, and then 19.2/4=4.8 feet

Each side would be 4.8 feet

8 0

3 years ago

Which of the following binomials is a factor of 22 + 7 −9 ?

Kipish [7]

B i think..............

8 0

3 years ago

Ivan has cut 19 pieces of reinforcing bar (rebar) that are each 1.14 meters long. What is the total length of the rebar used fo

madreJ [45]

Answer:

The total length of rebar used is 21.66 meters.

Step-by-step explanation:

Given:

Ivan had cut a reinforcing bar in 19 pieces and length of each bar is 1.14 meters.

Number of pieces = 19

Length of each piece = 1.14

We need to find the total length of reinforcing bar.

To calculate the total length we will multiply number of pieces with length of each piece.

Hence,

Total length of rebar = Number of pieces × Length of each piece = $19\times1.14 = 21..66 m$

Rounding to nearest hundred = 21.66 m

Hence the total length of reinforcing bar is 21.66 meters.

4 0

3 years ago