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3 years ago

What is the sum of 13 + (-8)? -5 5 -21 21

Mathematics

2 answers:

Usimov [2.4K]3 years ago

7 0

5 is the sum (b) ahhhhahaha sorry this has to be 20 characters long

maxonik [38]3 years ago

6 0

Answer:

Step-by-step explanation:

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Please help me.........

marishachu [46]

Answer:

126 square feet

Step-by-step explanation:

The formula for the area of a triangle is ...

A = (1/2)bh . . . . . where b is the base length and h is the height

Here, you have a triangular face that has a base of 6 ft and a height of 14 ft. Its area is ...

A = (1/2)(6 ft)(14 ft) = 42 ft^2

The lateral area of the pyramid consists of 3 such triangles, so the lateral area is ...

LA = 3·(42 ft^2) = 126 ft^2

6 0

3 years ago

Find the measures of the angles of the triangle whose vertices are A = (-3,0) , B = (1,3) , and C = (1,-3).A.) The measure of ∠A

alekssr [168]

Answer:

$\theta_{CAB}=128.316$

$\theta_{ABC}=25.842$

$\theta_{BCA}=25.842$

Step-by-step explanation:

A = (-3,0) , B = (1,3) , and C = (1,-3)

We're going to use the distance formula to find the length of the sides:

$r= \sqrt{(x_1-x_2)^2+(y_1-y_2)^2+(z_1-z_2)^2}$

$AB= \sqrt{(-3-1)^2+(0-3)^2}=5$

$BC= \sqrt{(1-1)^2+(3-(-3))^2}=9$

$CA= \sqrt{(1-(-3))^2+(-3-0)^2}=5$

we can use the cosine law to find the angle:

it is to be noted that:

the angle CAB is opposite to the BC.

the angle ABC is opposite to the AC.

the angle BCA is opposite to the AB.

to find the CAB, we'll use:

$BC^2 = AB^2+CA^2-(AB)(CA)\cos{\theta_{CAB}}$

$\dfrac{BC^2-(AB^2+CA^2)}{-2(AB)(CA)} =\cos{\theta_{CAB}}$

$\cos{\theta_{CAB}}=\dfrac{9^2-(5^2+5^2)}{-2(5)(5)}$

$\theta_{CAB}=\arccos{-\dfrac{0.62}}$

$\theta_{CAB}=128.316$

Although we can use the same cosine law to find the other angles. but we can use sine law now too since we have one angle!

To find the angle ABC

$\dfrac{\sin{\theta_{ABC}}}{AC}=\dfrac{\sin{CAB}}{BC}$

$\sin{\theta_{ABC}}=AC\left(\dfrac{\sin{CAB}}{BC}\right)$

$\sin{\theta_{ABC}}=5\left(\dfrac{\sin{128.316}}{9}\right)$

$\theta_{ABC}=\arcsin{0.4359}\right)$

$\theta_{ABC}=25.842$

finally, we've seen that the triangle has two equal sides, AB = CA, this is an isosceles triangle. hence the angles ABC and BCA would also be the same.

$\theta_{BCA}=25.842$

this can also be checked using the fact the sum of all angles inside a triangle is 180

$\theta_{ABC}+\theta_{BCA}+\theta_{CAB}=180$

$25.842+128.316+25.842$

$180$

6 0

3 years ago

Read 2 more answers

Order least to greatest 0.5,3.16,0.75,11/48

lys-0071 [83]

11/48=.23

11/48, .5, .75, 3.16

Hope this helps

8 0

3 years ago

The figure consists of a quarter circle and a parallelogram. What is the area of the composite figure? Use 3.14 for n 76, Round

asambeis [7]

A is the answer i think

3 0

2 years ago

MORNING LOVES! LETS TALK ABOUT 7TH GRADE MATH!

Ipatiy [6.2K]

Answer:

ahh yes, let us talk about the mathematical experience you'll have to go through in your 7th grade year

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers