Matematika Smp Klas 9 Materi Kesebangunan

1.

Segitiga ABC dan Segitga DEF kongruen, pernyataan berikut yang benar adalah ... .

a. AB = DE

B. BC = EF

C. BC = DF

D. AC = EF

The statement "AC = EF" is correct because in congruent triangles, corresponding sides are equal in length. Therefore, if triangle ABC is congruent to triangle DEF, it means that side AC is equal in length to side EF.

Explanation

The statement "AC = EF" is correct because in congruent triangles, corresponding sides are equal in length. Therefore, if triangle ABC is congruent to triangle DEF, it means that side AC is equal in length to side EF.

2. Bangun- bangun berikut sebangun dengan ubin yang berukuruan 30 cmx 30 cm, kecuali ... .

A. Buku tulis dengan ukuran 20cm x 15 cm

B. Karpet berukuran 4 m x 4m

C. Ring tinju dengan ukuran 5m x 5m

D. Tikar berukuran 2m x 2m

The given statement states that all the shapes mentioned are similar to tiles measuring 30 cm x 30 cm, except for the size of a notebook which is 20 cm x 15 cm. This means that the notebook is not proportional to the tiles and does not have the same dimensions. Therefore, the correct answer is A. Buku tulis dengan ukuran 20cm x 15 cm.

Explanation

The given statement states that all the shapes mentioned are similar to tiles measuring 30 cm x 30 cm, except for the size of a notebook which is 20 cm x 15 cm. This means that the notebook is not proportional to the tiles and does not have the same dimensions. Therefore, the correct answer is A. Buku tulis dengan ukuran 20cm x 15 cm.

3. Sebuah fotodengan tinggi 8 cm dan lebar 6 cm, diperbesar hingga lebarnya menjadi 21cm, Luas foto setelah diperbesar adalah ... .

The correct answer is 588 cm². To find the area of the photo after it is enlarged, we need to determine the scale factor of the enlargement. The scale factor is found by dividing the new width (21 cm) by the original width (6 cm), which gives us a scale factor of 3.5. To find the area, we square the scale factor and multiply it by the original area. The original area is 8 cm x 6 cm = 48 cm². Multiplying 48 cm² by 3.5² gives us 588 cm².

Explanation

The correct answer is 588 cm². To find the area of the photo after it is enlarged, we need to determine the scale factor of the enlargement. The scale factor is found by dividing the new width (21 cm) by the original width (6 cm), which gives us a scale factor of 3.5. To find the area, we square the scale factor and multiply it by the original area. The original area is 8 cm x 6 cm = 48 cm². Multiplying 48 cm² by 3.5² gives us 588 cm².

Submit

4. Pada siang hari yang cerah, satu regu pramuka mendapat tugas untuk menghitung tinggi sebuah pohon tanpa harus memanjat. Salh seaorang anggota mengambi tongkat yang panjangnya 160 cm, kemudian tongkat tersebut di dirikan tegak lurus di atas tanah rata. Anggota pramuka yang lain mengukur panjang bayangan pohon dan panjang bayangan tongkat. Ternyata, panjang bayangan pohon 375 cm dan panjang bayangan tongkat 80 cm. maka tinggi pohon tersebut adalah … .

8 m

7,5 m

6 m

3,75 m

The height of the tree can be calculated using the concept of similar triangles. The length of the tree's shadow is proportional to the height of the tree, while the length of the stick's shadow is proportional to the length of the stick. By setting up a proportion, we can find the height of the tree. The length of the tree's shadow is 375 cm and the length of the stick's shadow is 80 cm. Therefore, the height of the tree is (375 cm / 80 cm) * 160 cm = 7.5 m.

Explanation

The height of the tree can be calculated using the concept of similar triangles. The length of the tree's shadow is proportional to the height of the tree, while the length of the stick's shadow is proportional to the length of the stick. By setting up a proportion, we can find the height of the tree. The length of the tree's shadow is 375 cm and the length of the stick's shadow is 80 cm. Therefore, the height of the tree is (375 cm / 80 cm) * 160 cm = 7.5 m.

5.

Sebuah karton dengan ukuran 30cm x 50cm sebangun dengan foto ditempel seperti gambar di samping, jika sisi kanan sisi atas, sisi kanan dan kiri foto berjarak 5cm, maka lebar foto adalah ....cm

The width of the photo can be calculated by subtracting the distances between the sides of the photo and the sides of the cardboard from the width of the cardboard. Since the distances between the sides of the photo and the sides of the cardboard are all 5cm, we can subtract 5cm from both sides of the cardboard. Therefore, the width of the photo is 30cm - 5cm - 5cm = 20cm.

Explanation

The width of the photo can be calculated by subtracting the distances between the sides of the photo and the sides of the cardboard from the width of the cardboard. Since the distances between the sides of the photo and the sides of the cardboard are all 5cm, we can subtract 5cm from both sides of the cardboard. Therefore, the width of the photo is 30cm - 5cm - 5cm = 20cm.

Submit

6. Dua bangun berikut pasti sbangun

dua segitiga siku-siku

dua segitiga lancip

dua segitiga sama kaki

dua segitiga sama sisi

The given answer states that "dua segitiga sama sisi" (two equilateral triangles) are definitely congruent. This is because equilateral triangles have all sides and angles equal, so if we have two equilateral triangles, they will be congruent to each other. Therefore, the given answer is correct.

Explanation

The given answer states that "dua segitiga sama sisi" (two equilateral triangles) are definitely congruent. This is because equilateral triangles have all sides and angles equal, so if we have two equilateral triangles, they will be congruent to each other. Therefore, the given answer is correct.

7. Setiap bangun berikut pasti sebangun, kecuali .....

A. Dua bangun Lingkaran

B. Dua bangun Persegi

C. Dua bangun Belah ketupat

D. Dua bangun Segitiga sama sisi

Silahkan lanjutkan ke Soal Berikut

Explanation

Silahkan lanjutkan ke Soal Berikut

8. Sebuah tower mempunyai banyangan yang panjangnya 6,25 m. JIka sepotong kayu yang panjangnya 70 cm di tancapkan tegak lurus diatas tanah, maka panjang bayangannya 20 cm, Maka tinggi tower adalah ... .

437,5 m

218,7 m

43,75 m

21,87 m

The given question involves a shadow problem. The length of the shadow of the wooden stick is given as 20 cm, and the actual length of the stick is 70 cm. To find the height of the tower, we can use the concept of similar triangles. The ratio of the height of the tower to the length of the shadow is equal to the ratio of the length of the stick to the length of its shadow. Using this proportion, we can calculate the height of the tower as (70 cm * 6.25 m) / 20 cm = 21.87 m.

Explanation

The given question involves a shadow problem. The length of the shadow of the wooden stick is given as 20 cm, and the actual length of the stick is 70 cm. To find the height of the tower, we can use the concept of similar triangles. The ratio of the height of the tower to the length of the shadow is equal to the ratio of the length of the stick to the length of its shadow. Using this proportion, we can calculate the height of the tower as (70 cm * 6.25 m) / 20 cm = 21.87 m.