From a window 31.0 ft above the street, the angle of elevation to the top of the building across the street is 54.0° and the angle of depression to the base of this
building is 15.0°. Find the height of the building across the street.

e^-kt = n/n0 = 0.79  

-kt = ln 0.79  

t = - ln 0.79/0.0001  

= 2357 years

step-by-step explanation:

delaney would like to make a 5lb nut mixture that is 60% peanuts and 40% almonds.

she has several pounds of peanuts and several pounds of a mixture that is 20% peanuts and 80% almonds.

let 'p' represent the number of pounds of peanuts needed to make the new mixture, and  

let 'm' represent the number of pounds of the 80% almond-20% peanut mixture.

:

p + m = 5

therefore

m = (5-p)

write an equation based on the percent of peanuts

1p + .2m = .6(5)

replace m with (5-p)

p + .2(5-p) = .6(5)

p + 1 - .2p = 3

p - .2p = 3 - 1

.8p = 2

p = 2/.8

p = 2.5 lbs of peanuts required

then

5 - 2.5 = 2.5 lbs of the peanut/almond mixture required

:

a) what is the system that models this situation?

p + m = 5

1p + .2m = .6(5)

the transitive property of equality.

step-by-step explanation:

the correct answer is:

the transitive property of equality.

explanation:

we know that  ∠bcd is congruent to  ∠pbc. we also know that  ∠pbc is congruent to  ∠bad.

we can substitute  ∠bad for  ∠pbc in the first angle congruence statement to give us:

∠bcd is congruent to  ∠bad.

algebraically, the transitive property states if a=b and b=c, then a=c. it basically allows us to substitute equal values. since that is what we did, this is the transitive property.

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