Iron makes up 4.5% of the Earth's crust. Which is another way to write 4.5% of a value?

The Hu family goes out for lunch, and the price of the meal is $59. The sales tax on the meal is 7%, and the family also leaves

Setler79 [48]

$71.98 is the total cost for the meal
59.00
+ 4.13
+ 8.85
======
71.98

7 0

3 years ago

The numerical coefficient of -2pqr

VMariaS [17]

Answer: -2

Explanation: The coefficient is the number to the left of the variable.

Another example would be that 10xy has the coefficient 10.

Something like x^2 has coefficient 1 because x^2 = 1x^2.

7 0

3 years ago

Is 6 – 2 positive or negative

Kaylis [27]

Positive because it does not go less than 0.

6 0

3 years ago

Read 2 more answers

Consider the case of a triangle with sides 5, 12, and the angle between them 90°.

Daniel [21]

Answer:

a) Applying Pithagoras Theorem

b) Trigonometric relations

c) No we can not

d) No we can not

e) See step-by-step explanation

f) See step-by-step-explanation

Step-by-step explanation:

a) The easiest method for calculating the missing side is applying Pithagoras Theorem

c² = a² + b²

c² = (5)² + (12)² ⇒ c² = 25 + 144 ⇒ c² = 169 ⇒ c = 13

b) The easiest method to find the missing angles, is to calculate the sin∠ and then look for arcsin fuction in tables.

sin ∠α = 5/13 sin ∠α = 0.3846 ⇒ arcsin (0.3846 ) α = 23⁰

Now we can either get the other angle subtracting 180 - 90 - 23 = 67⁰

Or calculating sinβ = 12 /13 sinβ = 0.9230 arcsin(0.9230) β = 67⁰

c) The law of cosines should not be applied to right triangles, in fact for instance in our particular case we have:

Question a)

c² = a² + b² - 2*a*b*cos90⁰ (law of cosines ) but cos 90⁰ = 0

then c² = a² + b² which is the expression for theorem of Pithagoras

In case you look for calculating the missing angles

c² = a² + b² - 2*5*13*cos α

169 = 25 + 144 - 2*5*13* cos α

As you can see 169 - 25 - 144 = 0

Then we can not apply law of cosine in right triangles, we shoul apply trigonometric relations and Pithagoras theorem, and as we saw you can get the expression of Pithagoras theorem from cosine law

c² = a² + b² - 2*a*b*cos∠90° cos ∠ 90° = 0

Then c² = a² + b²

3 0

3 years ago

Cada par de puntos determina una recta con la pendiente dada. Halla el valor de la incógnita en cada caso: a. (3,2);(4,x); m=1 b

True [87]

Answer:

a=3,b=0,c=5,d=-4/21

Step-by-step explanation:

The formule we use to get the slope is:

m = $\frac{y2-y1}{x2-x1}$

a. (3,2);(4,x); m=1

$\frac{x-2}{4-3}=1$ → x= (1)(4-3)+2 → 3

b. (b,-1);(2,-2); m=-1/2

$\frac{-2-(-1)}{2-b}=\frac{-1}{2}$ → -1= ( $\frac{-1}{2}$ )(2-b) → $\frac{-1}{\frac{-1}{2} }-2$ → 0

c. (5,d);(9,2); m=-3/4

$\frac{2-d}{9-5}=\frac{3}{4}$ → d= ( $\frac{-3}{4}$ )(9-5)-2 → 5

d. (-1/3,3/4);(h,5/6); m=7/12

$\frac{\frac{5}{6}-\frac{3}{4} }{h-\frac{-1}{3} }=\frac{7}{12}$ → $\frac{5}{6}-\frac{3}{4}$ = $\frac{7}{12}$ ( ${h-\frac{-1}{3} }$ ) → $\frac{-4}{21}$

We get this equation with the original one:

y=mx+b

There are three forms of linear equations:

point-slope form y2-y1=m(x2-x1)

standard form Ax + By + C = 0 or Ax + By = C

and slope-intercept form y=mx+b

4 0

4 years ago