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3 years ago

Help please!

Mathematics

1 answer:

ch4aika [34]3 years ago

8 0

Answer:

Step-by-step explanation:

Sry but I only did 1,2,5,6,7&8

But am not sure if am correct just try

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The perimeter of a triangular field is 120m. Two of the sides are 21m and 40m.Calculate the largest angle of the field.

Mama L [17]

Answer:

the largest angle of the field is 149⁰

Step-by-step explanation:

Given;

perimeter of the triangular filed, P = 120 m

length of two known sides, a and b = 21 m and 40 m respectively

The length of the third side is calculated as follows;

a + b + c = P

21 m + 40 m + c = 120 m

61 m + c = 120 m

c = 120 m - 61 m

c = 59 m

↓ ↓

A → → → → → → → → → → → C

Consider ABC as the triangular field;

Angle A is calculated by applying cosine rule;

$a^2 = b^2 + c^2 - 2bc \ Cos A\\\\Cos \ A = \frac{b^2 + c^2 - a^2}{2bc} \\\\Cos \ A = \frac{40^2 + 59^2 - 21^2}{2 \times 40 \times 59} \\\\Cos \ A = 0.983\\\\A = Cos ^{-1} (0.983)\\\\A = 10.6 \ ^0$

Angle B is calculated as follows;

$Cos \ B = \frac{a^2 + c^2 - b^2}{2ac} \\\\Cos \ B = \frac{21^2 + 59^2 - 40^2}{2 \times 21 \times 59} \\\\Cos \ B = 0.937\\\\B= Cos ^{-1} (0.937)\\\\B = 20.5 \ ^0$

Angle C is calculated as follows;

$Cos \ C = \frac{a^2 + b^2 - c^2}{2ab} \\\\Cos \ C = \frac{21^2 + 40^2 - 59^2}{2 \times 21 \times 40} \\\\Cos \ C = -0.857\\\\C = Cos ^{-1} (-0.857)\\\\C = 149\ ^0$

Therefore, the largest angle of the field is 149⁰.

8 0

3 years ago

5/6+2i Aka 5 ___ 6+2y Ignore my answer its probably wrong

liberstina [14]

Answer:

(3/4) -(1/4)i

Step-by-step explanation:

Your answer is correct.

$\dfrac{5}{6+2i}=\dfrac{5(3-i)}{2(3+i)(3-i)}=\dfrac{5(3-i)}{2(9+1)}\\\\=\dfrac{3-i}{4}=\dfrac{3}{4}-\dfrac{1}{4}i$

8 0

3 years ago

The perimeter of a rectangle is about 13.9 cm. If you double the width of the rectangle the perimeter is about 17.8 cm. Find the

fredd [130]

Answer:

5cm by 1.95cm

Step-by-step explanation:

Let the length of the rectangle be x

Let the width be y

Perimeter of a rectangle = 2x + 2y

If the initial perimeter of a rectangle is about 13.9 cm, then;

13.9 = 2x + 2y ..... 1

If when the width is double the perimeter is 17.8cm, then;

17.8 = 2x + 4y ..... 2

Subtract 1 from 2;

13.9 - 17.8 = 2y - 4y

- 3.9 = -2y

y = 3.9/2

y = 1.95 cm

Substitute y = 1.95 into 1 to get x;

From 1;

13.9 = 2x + 2y

13.9 = 2x + 2(1.95)

13.9 = 2x + 3.9

2x = 13.9-3.9

2x = 10

x = 5 cm

Hence the dimension of the smaller triangle is 5cm by 1.95cm

7 0

3 years ago

Ben sells homemade cards at a craft fair. He wants to earn more than $50 at the fair. He sells his cards for $2 and he has alrea

Kryger [21]

Answer:

He must sell 8 cards to reach the minimum goal.

Step-by-step explanation:

Giving the following information:

He wants to earn more than $50 at the fair.

He sells his cards for $2 and he has already earned $36.

First, we need to calculate the money required to reach the minimum goal:

51 - 36= $15

Now, we write the inequality:

2*x >15

x= number of cards sold.

x>15/2

x> 7.5

He must sell 8 cards to reach the minimum goal.

7 0

3 years ago

Pls HELP I BEG YOUUUU

Stells [14]

Answer:

x = 60

Step-by-step explanation:

(x+22) + (x+6) + (x-28) = 180

x + 22 + x + 6 + x - 28 = 180

x + x + x + 22 + 6 - 28 = 180

3x = 180

x = 180/3

x = 60

6 0

3 years ago