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3 years ago

15

8 1/2=7 ?/2 NEED HELP ASAP:)

2 answers:

Alja [10]3 years ago

7 0

Answer:

3

Step-by-step explanation:

8 1/2 = 17/2 - 14/2 = 3/2

VARVARA [1.3K]3 years ago

3 0

Eight and one half is equal too seven and three halves

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10 points and brainliest

iris [78.8K]

Answer: D

Step-by-step explanation:

8 0

3 years ago

Which are vertical angles to 4?

Nikolay [14]

Answer: Angle 1 only

Vertical angles are angles formed when we cross two lines like this. They are opposite one another. The other pair of vertical angles are angle 2 and angle 3.

8 0

3 years ago

Use triangle ABC drawn below & only the sides labeled. Find the side of length AB in terms of side a, side b & angle C o

Brrunno [24]

Answer:

$AB = \sqrt{a^2 + b^2-2abCos\ C}$

Step-by-step explanation:

Given:

The above triangle

Required

Solve for AB in terms of a, b and angle C

Considering right angled triangle BOC where O is the point between b-x and x

From BOC, we have that:

$Sin\ C = \frac{h}{a}$

Make h the subject:

$h = aSin\ C$

Also, in BOC (Using Pythagoras)

$a^2 = h^2 + x^2$

Make $x^2$ the subject

$x^2 = a^2 - h^2$

Substitute $aSin\ C$ for h

$x^2 = a^2 - h^2$ becomes

$x^2 = a^2 - (aSin\ C)^2$

$x^2 = a^2 - a^2Sin^2\ C$

Factorize

$x^2 = a^2 (1 - Sin^2\ C)$

In trigonometry:

$Cos^2C = 1-Sin^2C$

So, we have that:

$x^2 = a^2 Cos^2\ C$

Take square roots of both sides

$x= aCos\ C$

In triangle BOA, applying Pythagoras theorem, we have that:

$AB^2 = h^2 + (b-x)^2$

Open bracket

$AB^2 = h^2 + b^2-2bx+x^2$

Substitute $x= aCos\ C$ and $h = aSin\ C$ in $AB^2 = h^2 + b^2-2bx+x^2$

$AB^2 = h^2 + b^2-2bx+x^2$

$AB^2 = (aSin\ C)^2 + b^2-2b(aCos\ C)+(aCos\ C)^2$

Open Bracket

$AB^2 = a^2Sin^2\ C + b^2-2abCos\ C+a^2Cos^2\ C$

Reorder

$AB^2 = a^2Sin^2\ C +a^2Cos^2\ C + b^2-2abCos\ C$

Factorize:

$AB^2 = a^2(Sin^2\ C +Cos^2\ C) + b^2-2abCos\ C$

In trigonometry:

$Sin^2C + Cos^2 = 1$

So, we have that:

$AB^2 = a^2 * 1 + b^2-2abCos\ C$

$AB^2 = a^2 + b^2-2abCos\ C$

Take square roots of both sides

$AB = \sqrt{a^2 + b^2-2abCos\ C}$

6 0

3 years ago

Three fourths a number plus 8 is 20 less than the number

VARVARA [1.3K]

Answer:

Equation: $\frac{3}{4}n+8=n-20$

Solve for n: n = 112

Step-by-step explanation:

To first set up the equation, you need to look at the verbal description and translate into numbers and operations:

'three fourths a number' = $\frac{3}{4} n$

'plus 8' = + 8

'is' =

'20 less' = - 20

'the number' = n

Put the expressions together:

'three fourths a number plus 8': $\frac{3}{4}n+8$

'20 less than the number': n - 20

Set them equal to each other and solve: $\frac{3}{4}n+8=n-20$

Add 20 to both sides: $\frac{3}{4}n+8+20=n-20+20$

Subtract $\frac{3}{4}n$ from both sides: $\frac{3}{4}n-\frac{3}{4}n+28=n-\frac{3}{4}n$

Multiply both sides by $\frac{4}{1}$ : $\frac{4}{1}28=\frac{1}{4}n\frac{4}{1}$

Solve for n: n = 112

7 0

3 years ago

How do i calculate percent accuracy? I got 20 questions out of 21 correct but I need to figure out the percent accuracy for anot

Mandarinka [93]

You need to do 20 divide by 21 to get a decimal. Then if you multiply the decimal by hundred you should get the percentage.

7 0

3 years ago