COHEA 8th Grade Test 1

What is the length of line segment EF if DE is 6ft and DF is 11ft and angle FDE is 40 degrees

Anna [14]

Answer:

The length of EF = 7.48 feet

Step-by-step explanation:

* Lets consider these tree segment formed triangle DEF

- We have the length of two sides and the measure of the

including angle between these two sides

* So we can use the cos Rule to find the length of the third side

- The cos rule ⇒ a² = b² + c² - 2bc cosA

# a is the side opposite to angle A

# b is the side opposite to angle B

# c is the side opposite to angle C

# Angle A is the including angle between b and c

* In the problem

∵ DE = 6 feet

∵ DF = 11 feet

∵ m∠FDE = 40° ⇒ including angle between DE and DF

and opposite to EF

- By using cos Rule

∴ (EF)² = (DE)² + (DF)² - 2(DE)(DF) cos∠FDE

∴ (EF)² = (6)² + (11)² - 2(6)(11) cos(40)

∴ (EF)² = 55.882133 ⇒ take square root for both sides

∴ EF = 7.47543 ≅ 7.48 feet

* The length of EF = 7.48 feet

6 0

2 years ago

An image of a parabolic lens is projected onto a graph.The y-intercept of the graph is (0, 90), and the zeros are 5 and 9. Which

Gnesinka [82]

Step-by-step explanation:

If the zeros are 5 and 9, then the equation will have the form:

y = a (x–5) (x–9)

We know the point (0, 90) is on the curve, so we can use this to find the coefficient a:

90 = a (0–5) (0–9)

90 = 45a

a = 2

y = 2 (x – 5) (x – 9)

6 0

2 years ago

Read 2 more answers

the probability that people buy candy movies at 45% if they're 160 people in the theater about how many bought candy

goldenfox [79]

Answer:

72

Step-by-step explanation:

$160*\frac{45}{100} =72$

8 0

2 years ago

A hole is drilled in a sheet-metal component, and then a shaft is inserted through the hole. The shaft clearance is equal to dif

VashaNatasha [74]

Answer:

(A)

$P(X \geq 0.8) = \int\limits_{0.8}^{\infty} f(x) \, dx = \int\limits_{0.8}^{1} 1.25(1-x^4) \, dx = 0.08192$

(B)

Then the cumulative function would be

$CF(x) = 1.25x - 0.25x^5$ if 0<x<1

0 otherwise.

Step-by-step explanation:

(A)

We are looking for the probability that the random variable X is greater than 0.8.

$P(X \geq 0.8) = \int\limits_{0.8}^{\infty} f(x) \, dx = \int\limits_{0.8}^{1} 1.25(1-x^4) \, dx = 0.08192$

(B)

For any $x$ you are looking for the probability $P(X \geq x)$ which is

$P(X \geq x) = \int\limits_{-\infty}^{x} 1.25(1-t^4) dt = \int\limits_{0}^{x} 1.25(1-t^4) dt = 1.25x - 0.25x^2$

Then the cumulative function would be

$CF(x) = 1.25x - 0.25x^5$ if 0<x<1

0 otherwise.

5 0

2 years ago

A County Superintendent of Highways is interested in the numbers of different types of vehicles that regularly travel within his

Karolina [17]

Answer:

a) The ratio of passenger cars to pickup trucks is $\frac{5}{7}$

The ratio of pickup trucks to passenger cars is $\frac{7}{5}$

The ratio of passenger cars to total vehicles is $\frac{5}{12}$

The ratio of pickup trucks to total vehicles is $\frac{7}{12}$

b) The tape diagram is shown in the attached picture.

c) The tape diagram has 12 equal-sized parts.

d) The total quantity that the tape diagram represent is 192.

e) The value of each individual part of the tape is 16.

f) There were registered 80 passenger cars and 112 pickup trucks.

Step-by-step explanation:

a) According to the information in the problem, that for every 5 passenger cars registered, there were 7 pickup trucks registered.

So the ratios are:

Passenger cars to pickup trucks: $\frac{5}{7}$

Pickup trucks to passenger cars: $\frac{7}{5}$

If we calculate the total vehicles: 5+7=12

So, we can get two ratios more:

Passenger cars to total vehicles is $\frac{5}{12}$

Pickup trucks to total vehicles is $\frac{7}{12}$

b) We make a tape diagram where each box represents a vehicle so we draw 5 boxes for cars and 7 boxes for pickup trucks.

c) If we count the total quantity of boxes, there are 12.

d) This diagram represents the total quantity of registrations in August which is 192.

e) To get the representation of each part of the tape diagram we have to divide 192 by 12. 192÷12=16

f) Finally, we multiply 16 by the number of boxes of each type of vehicle:

Cars: 16×5=80

Pickup trucks: 16×7=112

6 0

2 years ago