All categories

3 years ago

How to do proof problems in geometry

1 answer:

Crank3 years ago

6 0

First, start with your given. If your given has the words: bisect or midpoint, then the next step will be the definition of that.

You might be interested in

In triangle ΔABC, ∠C is a right angle and CD is the height to

Zina [86]

Answer:

$m\angle CDB=90\\m\angle CBD=90-\alpha\\m\angle BCD=\alpha\\\\m\angle CDA=90\\m\angle CAD=\alpha\\m\angle ACD=90-\alpha$

Step-by-step explanation:

The triangles are drawn below.

CD is perpendicular to AB as CD is height to AB.

Therefore, angles $m\angle CDB=m\angle CDA=90$ °

So, triangles ΔCBD and ΔCAD are right angled triangles.

Now, from the right angled triangle ΔABC,

$m\angle A+m\angle B =90\\\alpha+m\angle B=90\\m\angle B=90-\alpha$

From ΔCBD,

$m\angle CBD$ is same as $m\angle B$ .

So, $m\angle CBD=90-\alpha$

$m\angle BCD+m\angle BDC =90\\m\angle BCD+90-\alpha=90\\m\angle BCD=\alpha$

Now, from ΔCAD,

$m\angle CAD$ is same as $m\angle A$

So, $m\angle CAD=\alpha$

$m\angle CAD+m\angle ACD =90\\\alpha+m\angle ACD=90\\m\angle ACD=90-\alpha$

Hence, the unknown angles of both the triangles are:

$m\angle CDB=90\\m\angle CBD=90-\alpha\\m\angle BCD=\alpha\\\\m\angle CDA=90\\m\angle CAD=\alpha\\m\angle ACD=90-\alpha$

5 0

2 years ago

The unknown measures of one triangle are about:

olga_2 [115]

Answer: but I need the points sorri

8 0

3 years ago

Jason has 56 pennies to stack equally in 8 piles. Which equation can help you find 56 = 8?

Arada [10]

Answer:

Step-by-step explanation:

56 divided by 8 . 56/8. 56/8 = 7

8 0

2 years ago

Read 2 more answers

Which symbol replaces the box to make the statement true?

Karolina [17]

Answer:

0. toab1. The right answer for K12 is ( > ) I Took the test and is correct. 4×16-16 > 4× [24-2× (4+8)] heart outlined. Thanks 0. star outlined. star outlined. star outlined.

8 0

2 years ago

I forgot how to do this, can someone help me-

Artyom0805 [142]

Step-by-step explanation:

1) x/20 = -9

By cross multiplication,

x = -180

2) -168 = -14k

k = -168/-14

k = 12

3) -5m = -50

m = 10

4) -320 = -20n

n = 16

5) -4 = x - 5

x = 1

6) -6(-8 + n) = -54

42 - 6n = -54

-6n = -54 -52

6n = 106

n = 17.6

7) 3(x - 9) = -3

3x - 27 = -3

3x = 24

x = 8

8) 9k + 3 = -78

9k = -81

k = -9

9)4 + (n/4) = 8

By taking LCM,

16 + n/4 = 8

16 + n = 32

n = 16

10) -5r + 7 = -73

-5r = -80

r = 16

Hope it helps.

6 0

2 years ago