Full Grade 3 test

A triangle is classified by its greatest angle.

• If one angle is exactly 90°, the triangle is right-angled.
• If one angle is greater than 90°, the triangle is obtuse-angled.
• If all three angles are less than 90°, the triangle is acute-angled.

Find the greatest given angle and use these conditions to select the triangle type.

The denominator is the number written below the fraction bar. It shows how many equal parts the whole is divided into.

The numerator is written above the fraction bar, so do not confuse it with the denominator.

Rule: select the bottom number of the fraction.

For three segments to form a triangle, the third side must be shorter than the sum of the two given sides and longer than their difference.

1. Add the given side lengths: {a} + {b}. The third side must be shorter than this sum.
2. Find the difference between the given side lengths: |{a} − {b}|. The third side must be longer than this difference.
3. Choose the listed length that satisfies both conditions.

Rule: if the third side has length c, then |{a} − {b}| < c < {a} + {b}.

All four sides of a square have the same length.

1. Divide the perimeter by 4 to find the length of one side.
2. Multiply the side length by itself.
3. Write the answer in square centimetres.

Formula: side = perimeter ÷ 4, area = side × side.

The numerator is the number written above the fraction bar. It shows how many equal parts are taken.

The denominator is written below the fraction bar, so do not confuse it with the numerator.

Rule: select the top number of the fraction.

A triangle is classified by comparing the lengths of all three sides.

• If all three sides are equal, the triangle is equilateral.
• If exactly two sides are equal, the triangle is isosceles.
• If all three side lengths are different, the triangle is scalene.

Compare the three given lengths and select the matching type.

Both fractions have the same numerator, so the same number of parts is taken in each case. Only the size of those parts is different.

1. Compare the denominators written below the fraction bars.
2. A greater denominator means that the whole is divided into more parts, so each part is smaller.
3. The fraction with the smaller denominator is greater.
4. Place > or < between the fractions, with the wide side of the sign facing the greater fraction.

Rule: when numerators are equal, the fraction with the smaller denominator is greater.

The area of a rectangle shows how many square units fit inside it.

1. Identify the length and width of the rectangle.
2. Multiply the length by the width.
3. Write the answer in square units.

Formula: A = a × b.