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BaLLatris [955]

3 years ago

8

What is a counterexample for if a shape has 4 sides its a rectangle

2 answers:

Mrrafil [7]3 years ago

6 0

parallelogram

Step-by-step explanation:

it has 4 sides but is not a rectangle

Rasek [7]3 years ago

5 0

Using numbers it helps label the rectangle

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Pls answer the question attached

barxatty [35]

$\huge\mathfrak{\underline{answer:}}$

$\large\bf{\angle ACD = 105°}$

__________________________________________

$\large\bf{\underline{Here:}}$

BCD is an isosceles right triangle , right angled at D
ABC is an equilateral triangle

$\large\bf{\underline{To\:find:}}$

∠ ACD

$\large\bf{In\: triangle\:ABC:}$

❒ Sum of all angles is 180° , since it is an equilateral triangle all the three angles would be same

$\large\bf{\underline{So}}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle ACB = \frac{180}{3}}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle ACB = 60°}$

$\large\bf{In\: triangle\:BDC}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle D = 90°}$

$\bf{⟼\angle DBC =\angle DCB }$ (Isosceles triangle)

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle DBC + \angle BDC + \angle DCB = 180° }$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼2\angle DCB + 90° = 180°}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼2\angle DCB = 180 -90}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle DCB = \frac{90}{2}}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟼\angle DCB = 45°}$

$\large\bf{\underline{Therefore,}}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟹\angle ACD = \angle ACB + \angle DCB}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\bf{⟹\angle ACD = 60+45}$

‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎‎‎ ‎ ‎ $\large\bf{⟹\angle ACD = 105°}$

6 0

3 years ago

Do the ratios 1/2 and 6/12 form a proportion

lawyer [7]

Answer:

Step-by-step explanation:

Yes because 6 is 1/2 of 12

6 0

3 years ago

Read 2 more answers

Mika can eat 21 hot dogs in 6 minutes. She wants to know how many minutes left it would take her to eat 35 hot dogs if she can k

liubo4ka [24]

It would take her 10min to finish 35 hot dogs because 21 divided by 6 equals 3.5 so in six minutes she eats 3.5 hot dogs per minute. Multiply 3.5 by ten you get 35

7 0

3 years ago

If AE=6x-55 and EC=3x-16, find DB. (Hint: Find x first and then substitute.)

erica [24]

<u>Given</u>:

Given that ABCD is a rectangle.

The diagonals of the rectangle are AC and DB.

The length of AE is (6x -55)

The length of EC is (3x - 16)

We need to determine the length of the diagonal DB.

<u>Value of x:</u>

The value of x can be determined by equating AE and EC

Thus, we have;

$AE=EC$

Substituting the values, we get;

$6x-55=3x-16$

$3x-55=-16$

$3x=39$

$x=13$

Thus, the value of x is 13.

<u>Length of AC:</u>

Length of AE = $6(13)-55=78-55=23$

Length of EC = $3(13)-16=39-16=23$

Thus, the length of AC can be determined by adding the lengths of AE and EC.

Thus, we have;

$AC=AE+EC$

$AC=23+23$

$AC=46$

Thus, the length of AC is 46.

<u>Length of DB:</u>

Since, the diagonals AC and DB are perpendicular to each other, then their lengths are congruent.

Hence, we have;

$AC=DB$

$46=DB$

Thus, the length of DB is 46.

6 0

3 years ago

Whats the answer, to the question below

NISA [10]

The answer to this problem is 5.

6 0

3 years ago

Read 2 more answers