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2 years ago

Oliver’s room is 3 yards wide. The perimeter of the room is 14 yards.

1 answer:

8 0

<span>n Billy's class, 75% of his classmates had brown hair. 18 of his classmates had brown hair. What's the total number of students in his class?</span>

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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

2 years ago

Read 2 more answers

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avanturin [10]

C. The functions fans g have different axes of symmetry and different minimum values

7 0

2 years ago

Heather wants to put some bricks around her campfire.

Novosadov [1.4K]

Answer:

ibk looks it up please hope this helps

3 0

2 years ago

Some friends shared 2 bags of chips. If each person got 2/3 of a bag of chips, how many friends were there?

quester [9]

Answer:

1 1/3

Step-by-step explanation:

5 0

3 years ago

Daisy works at an ice-cream parlor. She is paid $10 per hour for the first 8 hours she works in a day. For every extra hour she

tester [92]

Answer:

The expression giving her net earnings for a day with more than 8 hours worked is X = 80 + 15H, where H means "extra hours worked".

Step-by-step explanation:

Given that Daisy works at an ice-cream parlor earning $10 per hour for the first 8 hours she works in a day, and 1.5 times her hourly wage for every extra hour she works, in order to know how much can she make in a day working more than 8 hours the following equation has to be made:

X = (8 x 10) + (H x (1.5 x 10))

X = 80 + 15H

Therefore, if Daisy works 13 hours, the equation works as follows:

X = 80 + 15x13

X = 80 + 195

X = 275

3 0

2 years ago