10/24 x 100 = 41.66
Approximately 42% of her day
Answer:
65°
Step-by-step explanation:
To obtain Angle A, we use the cosine rule ;
Cos A = (b² + c² - a²) / 2bc
Cos A = (12² + 14² - 14²) / 2(12)(14)
Cos A = 144 / 336
A = Cos^-1(144/336)
A = 64.62°
A = 65°
To factor both numerator and denominator in this rational expression we are going to substitute

with

; so

and

. This way we can rewrite the expression as follows:

Now we have two much easier to factor expressions of the form

. For the numerator we need to find two numbers whose product is

(30) and its sum

(-11); those numbers are -5 and -6.

and

.
Similarly, for the denominator those numbers are -2 and -5.

and

. Now we can factor both numerator and denominator:

Notice that we have

in both numerator and denominator, so we can cancel those out:

But remember than

, so lets replace that to get back to our original variable:

Last but not least, the denominator of rational expression can't be zero, so the only restriction in the variable is

