Question

6 name each triangle based on its sides (equilateral, isosceles, or scalene) and its angles (acute, obtuse, or right)
which choice shows 4,930?
a) 3 thousands, 19 hundreds, 30 tens
b) 4 thousands, 93 hundreds
c) 3 thousands, 19 hundreds, 3 ones
d) 4 thousands, 8 hundreds, 13 tens
4,000 + 800 + 130 = 4,930

1. which sentence about the rectangular shape below is not true?

9 cm
4 cm
a) the perimeter is 2 x (4 cm + 9 cm)
b) the area is 36 square cm
c) the perimeter is (2 x 9 cm) + (2 x 4 cm)
d) the area is 4 cm + 9 cm + 4 cm + 9 cm

Explanation:

Question 6:

First triangle:

• Observe the sides: Two sides are of equal length. So, it is an isosceles triangle.
• Observe the angles: All angles are less than 90 degrees, so it is an acute - angled triangle.

Second triangle:

• Observe the sides: All three sides are of equal length. So, it is an equilateral triangle.
• Since all angles in an equilateral triangle are 60 degrees (less than 90 degrees), it is an acute - angled triangle.

Third triangle:

• Observe the sides: All three sides have different lengths. So, it is a scalene triangle.
• Observe the angles: One angle is greater than 90 degrees, so it is an obtuse - angled triangle.

Question 7:

Analyze option a:

3 thousands is 3000, 19 hundreds is 1900, and 30 tens is 300. \(3000 + 1900+300=5200
eq4930\).

Analyze option b:

4 thousands is 4000, 93 hundreds is 9300. \(4000 + 9300=13300
eq4930\).

Analyze option c:

3 thousands is 3000, 19 hundreds is 1900, and 3 ones is 3. \(3000+1900 + 3=4903
eq4930\).

Analyze option d:

4 thousands is 4000, 8 hundreds is 800, and 13 tens is 130. \(4000+800 + 130=4930\).

Question 8:

Calculate the perimeter of the rectangle:

The formula for the perimeter of a rectangle is \(P = 2(l + w)\), where \(l = 9\mathrm{cm}\) and \(w = 4\mathrm{cm}\). So, \(P=2(9 + 4)=2\times13 = 26\mathrm{cm}\). Also, \(P=(2\times9)+(2\times4)=18 + 8=26\mathrm{cm}\).
The formula for the area of a rectangle is \(A=l\times w\), so \(A = 9\times4=36\mathrm{cm}^2\).

• Option a: \(2\times(4 + 9)=26\mathrm{cm}\), correct.
• Option b: \(9\times4 = 36\mathrm{cm}^2\), correct.
• Option c: \((2\times9)+(2\times4)=18 + 8=26\mathrm{cm}\), correct.
• Option d: Area is not \(4 + 9+4\). Area \(A=l\times w\), so this option is not true.

Answer:

• Question 6:
• First triangle: Isosceles, Acute - angled
• Second triangle: Equilateral, Acute - angled
• Third triangle: Scalene, Obtuse - angled
• Question 7: d. 4 thousands, 8 hundreds, 13 tens
• Question 8: d. The area is 4 cm + 9 cm+4 cm