Essential Formulas and Calculations
Area formulas are absolutely crucial for your exams. Remember that rectangles use length × width, triangles need ½ × base × height (always use vertical height!), and circles require πr². For parallelograms, it's simply base × height, whilst trapeziums use ½ × height.
Perimeter is just the distance around any shape's edge. For circles, we call this circumference and use C = πD or C = 2πr. These circle formulas pop up constantly in exam questions.
The triangle method is brilliant for rearranging formulas like speed = distance/time. Draw a triangle, put what you're finding at the top, cover it up, and what's left shows you the calculation. For instance, to find time, you'd calculate distance ÷ speed.
Top Tip: When dealing with bearings, always measure clockwise from the north line - this catches loads of students out!
Volume calculations follow simple patterns. Cuboids use length × width × height, whilst any prism uses cross-sectional area × length. Master these basics and you'll handle most volume questions with confidence.
Percentages become easy when you remember that finding x% means multiplying by x/100. For percentage changes, work out the percentage amount first, then add or subtract from your original value.
