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seropon [69]
3 years ago
15

Chalk is an ionic compound. Which is a property of all ionic compounds that makes chalk particularly useful for writing on a cha

lkboard? A a high melting point B hardness and brittleness C inability to dissolve in water D a multicolored appearance
Mathematics
2 answers:
Delicious77 [7]3 years ago
6 0

The correct answer is B. Hardness and brittleness

Explanation:

The ions in materials such as chalk and other ionic compounds are bonded by electrostatic forces. These features give ionic compound unique characteristics. This includes the fact these materials are usually hard, which means they do not deform easily and the fact these are brittle, which means they break easily.

These properties can be observed in chalk because the chalk itself keeps its shape or does not deform (hardness) but it breaks easily under pressure (brittleness), indeed due to this last property it is possible to write using chalk and due to the first property it is possible the chalk is a durable material.

nalin [4]3 years ago
5 0

Answer:

It’s B

Step-by-step explanation:

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In a trivia contest, players from teams and work together to earn as many points as possible for their team. Each team can have
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Answer:

The inequality for each quantity described is given as follows;

0 ≤ A + B + C + D + E ≤ 50

Step-by-step explanation:

The given information are;

The number of players each team can have = between 3 and 5

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The number of players in Elena's team = Elena + 4 = 5 players

The total number of points Elena's team earns at the end of the round is given as follows;

0 ≤ A + B + C + D + E ≤ 5 × 10

Where the variables A, B, C, D, and E are the points each of Elena and are  makes such that the minimum points is 0 + 0 + 0 + 0 + 0 = 0 and the maximum point is 10 + 10 + 10 + 10 + 10 = 5 × 10 = 50, which gives;

0 ≤ A + B + C + D + E ≤ 50.

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3 years ago
The diagram shows how cos θ, sin θ, and tan θ relate to the unit circle. Copy the diagram and show how sec θ, csc θ, and cot θ r
DIA [1.3K]
<span>Copy the diagram and show how sec θ, csc θ, and cot θ relate to the unit circle. 

The representation of the diagram is shown if Figure 1. There's a relationship between </span>sec θ, csc θ, and cot θ related the unit circle. Lines green, blue and pink show the relationship. 

a.1 First, find in the diagram a segment whose length is sec θ. 

The segment whose length is sec θ is shown in Figure 2, this length is the segment \overline{OF}, that is, the line in green.

a.2 <span>Explain why its length is sec θ.

We know these relationships:

(1) sin \theta=\frac{\overline{BD}}{\overline{OB}}=\frac{\overline{BD}}{r}=\frac{\overline{BD}}{1}=\overline{BD}

(2) </span>cos \theta=\frac{\overline{OD}}{\overline{OB}}=\frac{\overline{OD}}{r}=\frac{\overline{OD}}{1}=\overline{OD}
<span>
(3) </span>tan \theta=\frac{\overline{FD}}{\overline{OC}}=\frac{\overline{FC}}{r}=\frac{\overline{FC}}{1}=\overline{FC}
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Triangles </span>ΔOFC and ΔOBD are similar, so it is true that:

\frac{\overline{FC}}{\overline{OF}}= \frac{\overline{BD}}{\overline{OB}}<span>

</span>∴ \overline{OF}= \frac{\overline{FC}}{\overline{BD}}= \frac{tan \theta}{sin \theta}= \frac{1}{cos \theta} \rightarrow \boxed{sec \theta= \frac{1}{cos \theta}}<span>

b.1 </span>Next, find cot θ

The segment whose length is cot θ is shown in Figure 3, this length is the segment \overline{AR}, that is, the line in pink.

b.2 <span>Use the representation of tangent as a clue for what to show for cotangent. 
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It's true that:

\frac{\overline{OS}}{\overline{OC}}= \frac{\overline{SR}}{\overline{FC}}

But:

\overline{SR}=\overline{OA}
\overline{OS}=\overline{AR}

Then:

\overline{AR}= \frac{1}{\overline{FC}}= \frac{1}{tan\theta} \rightarrow \boxed{cot \theta= \frac{1}{tan \theta}}

b.3  Justify your claim for cot θ.

As shown in Figure 3, θ is an internal angle and ∠A = 90°, therefore ΔOAR is a right angle, so it is true that:

cot \theta= \frac{\overline{AR}}{\overline{OA}}=\frac{\overline{AR}}{r}=\frac{\overline{AR}}{1} \rightarrow \boxed{cot \theta=\overline{AR}}

c. find csc θ in your diagram.

The segment whose length is csc θ is shown in Figure 4, this length is the segment \overline{OR}, that is, the line in green.

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A local park rents cabins for people who want to vacation by the forest. The fee for the rental is $27 per night. There is also
Dmitrij [34]
(190-55)=135
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Solve the one step equation: -5a = -50
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Answer:

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