Geometry

The area of an equilateral triangle is calculated using the formula (sqrt(3)/4) multiplied by the side length squared. Substituting 6 yields (sqrt(3)/4) * 36, which simplifies to 9sqrt(3). Distractors like 12sqrt(3) or 18 result from using incorrect formulas, such as forgetting to square the side or omitting the division by 4.

The volume of a cube is calculated by cubing its side length, so 5 cubed equals 125. Option A is incorrect because 25 represents the area of a single face of the cube, which uses squaring rather than cubing. Option B is also wrong as it only represents three times the face area

The perimeter of a rectangle is 2(length + width) = 30, which simplifies to length + width = 15. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Option C is incorrect because 15 represents the sum of the length and width, not the width alone.
• !Distractors like 12sqrt(3) or 18 result from using incorrect formulas, such as forgetting to square the side or omitting the division by 4.
• !Option A is incorrect because 25 represents the area of a single face of the cube, which uses squaring rather than cubing.

Answer each from memory — you'll see instantly whether you're right and why.

Run a focused 10-question mini-mock on Geometry and see it stick.