Mary's ruler is red

Mary's ruler is red

Mary's ruler is red.

How to say ruler in English

ruler

That's my ruler

That's my ruler

Application of sine and cosine theorem
To measure the width of the river, select two points B and C on one bank, look at the marker a on the other bank, measure the angle CBA = 45 °, angle BCA = 75 ° and BC = 120m, and calculate the width of the river

Because the angle CBA is 45 ° and BCA is 75 ° in the triangle ABC, the angle BAC is 60 degrees and BC is 120m
Using sine theorem sinBAC:BC = Sincba: AC is √ 3 / 2:120 = √ 2 / 2: AC
So AC = 40 √ 6
In the same way sinBAC:BC =sinBCA :AB = √3/2 ：120 =(√6＋√2)/4:AB
So AB = 60 √ 2 + 20 √ 6
Using the triangle area formula, let the river width be h, s = 1 / 2 * BC * H = 1 / 2 * ac * AB * sinbac
That is s = 1 / 2 * 120 * BC = 1 / 2 * 40 √ 6 * (60 √ 2 + 20 √ 6) * √ 3 / 2
Therefore, the river width H = 60 + 20 √ 3

What is the form of the verb + ing?
And the back + ed is the past tense?
What's the difference?

To be doing is generally understood as the present continuous tense, and it may also be a primary table structure
I am watching TV
The book is interesting
Adding ed after a verb is not only a past tense, but also a past participle
If it's be v-ed, there are two situations: passive voice or main structure
The Olympic Games were held in Beijing last year
This is the main table

What is the law of "negation of negation"?

There are three laws of dialectics, which Hegel first expounded in logic, while Engels summarized and refined them from logic, thus making the laws of dialectics clearer

Change the following nouns into plural
teacher,desk,cap,dog,house,bus,box,peach,student,bed,city,scarf,hero,man,sheep,child.
bus,dictonary,chair,uncle,driver,sheep,knife,inan,vase,watch,horse,woman,match,horse,
woman,match,goat,party,child,bike,map,foot.

teachers,desks,caps,dogs,houses,buses,boxes,peaches,students,beds,cities,scarves,heroes,men,sheep,children.
buses,dictionaries,chairs,uncles,drivers,sheep,knives,inan?,vases,watches,horses,women,matches,horses,
women,matches,goats,parties,children,bikes,maps,feet.
I don't know what inan is, so I didn't change it. Do you type it wrong?

If acosb + bcosa = csinc, s = 14 (B2 + c2-a2), then ∠ B = ()
A. 90°B. 60°C. 45°D. 30°

According to the sine theorem, acosb + bcosa = 2rsinacosb + 2rsinbcosa = 2rsin (a + b) = 2rsinc = 2rsinc · sinc ∧ sinc = 1, C = π 2. ∧ s = 12ab = 14 (B2 + c2-a2), the solution is a = B, so ∠ B = 45 °. So choose C

Is there any difference between the translation of "two pairs of shoes" and "two pairs of shoes"

Two pairs of shoes is correct, which involves how to express plural when English quantifiers (such as piece, cup, bag, etc.) are collocated with nouns. Words like piece, cup, bag, etc. are countable nouns, so they can have plural, such as two pieces of..., three cups of

In the triangle ABC, AC = BC, the center line ad on the side of BC divides the circumference of the triangle into two parts of 12 cm and 15 cm, and finds three
Find the length of each side of the triangle ABC.

Let the base of an isosceles triangle be x and the waist be y
List the equations
x+y/2=12
y+y/2=15
or
x+y/2=15
y+y/2=12
The first set of solutions is obtained
x=7 y=10
The second group of Solutions
x=11 y=8
The length of each side is
7、10、10
and
11、8、8
-------------------
If you haven't learned the quadratic equation of two variables, you can do it
(15-12) = 3 indicates that the difference between the waist and the bottom is 3
If the waist is 3 longer than the bottom, then AC = BC = AB + 3
So AC + CD = 15 AB + BD = 12
∵ac=2cd ∴ 3cd=15 cd=5
∴ac=10 bc=ac=10 ab=ac-3=7
If the waist is 3 longer than the bottom, then AC = BC = ab-3
Then AC + CD = 12 AB + BD = 15
∵ac=2cd ∴ 3cd=12 cd=4
∴ac=8 bc=ac=8 ab=ac+3=11