Rachma Hanan Tiasto
11313244020
International Mathematics Education
Mathematics For Junior High School 2
11313244020
International Mathematics Education
Mathematics For Junior High School 2
Page 43, Number 1 (A Way to Presenting Relations)
1. Make a arrow diagram from set K
= (Pontianak, Medan, Padang, Kendari, Yogyakarta, Bandung, Semarang) to set P =
(West Java, Middle Java, DI Yogyakarta, North Sumatra, West Kalimatan, South
Sulawesi) that shows relation of “capital city of” .
First you determine the pair of set.
-
Pontianak is paired with West
Kalimantan because the capital city of West Kalimantan is Pontianak.
-
Medan is paired with North
Sumatra because the capital city of North Sumatra is Medan.
-
Padang is paired with West
Sumatra because the capital city of West Sumatra is Padang.
-
Kendari is paired with
Southeast Sulawesi because the capital city of Southeast Sulawesi is Kendari.
-
Yogyakarta is paired with
Southeast Sulawesi because the capital city of DI Yogyakarta is Yogyakarta.
-
Bandung is paired with
Southeast Sulawesi because the capital city of
West Java is Bandung.
-
Semarang is paired with
Southeast Sulawesi because the capital city of Middle Java is Semarang.
After you
determine the pair of each element, we make the diagram.
Page 223, Number 1 (Circumference andArea of Circle)
2. The radius of a circle which has diameter 28 cm is…
2. The radius of a circle which has diameter 28 cm is…
a.
12 cm c. 14 cm
b.
13 cm d. 15 cm
We know that the diameter of a circle is twice from the radius of the a circle or 2r. So, the formula is d = 2r or r = d / 2
We know that the diameter of a circle is twice from the radius of the a circle or 2r. So, the formula is d = 2r or r = d / 2
From the question above,
the diameter of a circle is 28 cm then 28 cm devided by 2 snd we will get 14
cm.
Thus 14 cm is the radius of
a circle and we choose a. 14 cm.
Page 155, Number 4 (Right Triangles)
3. The hypotenuse of right triangle is 8 cm long. If the lenght one of the legs is 5 cm, then the lenght of other leg is...
3. The hypotenuse of right triangle is 8 cm long. If the lenght one of the legs is 5 cm, then the lenght of other leg is...
a.
6.25 c. 8.25
b.
7.25 d. 9.25
Assumed that we have rigth triangle ABC.
We know that the lenght one of the legs is
5 cm and the hypotenuse is 8 cm. So, we will to find the length of other leg
with pythagoras theorem. The formula to find the leg is c2 = a2
– b2
Accordingly, 5 cm is b, x cm is c and 8 cm
is a.
So, we put the value to the formula
c2 = a2 - b2
x2 = 82- 52
x2 = 64 - 25
x2 = 39
x =
6.25
Page 127, Number 3 (Solving The Word Problem)
4. The price of seven kilograms of rice and two kilograms of sugar is Rp 44,000.00. While the price of five kilograms of rice and four kilograms of sugar is Rp 43,000.00. If the rice is notated by b and sugar is notated by g then the problem can be written in mathematical expression of...
4. The price of seven kilograms of rice and two kilograms of sugar is Rp 44,000.00. While the price of five kilograms of rice and four kilograms of sugar is Rp 43,000.00. If the rice is notated by b and sugar is notated by g then the problem can be written in mathematical expression of...
a. 7b + 2g = 44,000.00 and 5b + 4g =
43,000.00
b. 2b + 7g = 43,000.00 and 5b + 4g =
44,000.00
c. 7b + 2g = 44,000.00 and 4b + 5g =
43,000.00
d. 2b + 7g = 43,000.00 and 4b + 5g =
44,000.00
From the question above, change the given
information in the world word problem into mathematical expression. Assumed
that rice is b and sugar is g.
·
The
price of seven kilograms of rice and two kilograms of sugar is Rp 44,000.00.
So, 7b + 2g = 44,000.00.
·
The
price of five kilograms of rice and four kilograms of sugar is Rp 43,000.00.So,
5b + 4g = 43,000.00
Therefore you get mathematical expression.
Thus, 7b + 2g = 44,000.00
5b + 4g = 43,000.00
The answer is a.
Page 37, Number 20 (Operation of Algebraic Expression)
5. Mr. Yahya buys orange, apple, and grape as much as 12 kg in total. The orange is 2 kg heavier than the apple and 1 kg heavier than the grape. The weight of each friut bought by Mr. Yahya are...
5. Mr. Yahya buys orange, apple, and grape as much as 12 kg in total. The orange is 2 kg heavier than the apple and 1 kg heavier than the grape. The weight of each friut bought by Mr. Yahya are...
(Hint: let, o = orange’s weight, a = apples’s
weight, g = grape’s weight)
a. o = 3, a = 4, g = 5
b. o = 5, a = 4, g = 3
c. o = 4, a = 3, g = 5
d. o = 5, a = 3, g = 4
First, determine the each weight of fruit
that buy by Mr.Yahya.the total weight of fruit (orange, apple, and grape) that
Mr. Yahya buy is 12 kg. Accordingly, o + a + g = 12 kg .
The orange is 2 kg heavier than the apple.
So, from this information we get o = 2 + a (i) . Accordingly, the weight of
orange is the weight of apple plus 2.
The orange is 1 kg heavier than the grape.
So, from this information we get o = 1 + g (ii). Accordingly, the weight of orange is the
weight of grape plus 1.
So, we will use subsitution method.
(i)
o = 2
+ a (ii) o = 1 + g
a = o – 2 g = o – 1
then we subsitute
the equation that we get to
o + a + g = 12 kg
o + (o-2) + (o-1)
= 12 kg
3o – 3 =
12 kg
3o =
12 + 3
3o =
15
o =
5 kg
From the result
of the weight of orange we subsitute to the apple and grape.
The weight of
apple is 5 kg minus 2 kg equals 3 kg.
The weight of
grape is 5 kg minus 1 kg equals 4 kg.
Thus, the answer is d. o = 5, a = 3, g = 4
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