Area, perimeter and angles

A rectangular rug is 7 m long and 4 m wide. What is its area, in square metres?

A garden is a 6 m by 4 m rectangle with a 2 m by 2 m square cut out of one corner (for a shed). What is the area of the garden, in square metres?

The same garden: a 6 m by 4 m rectangle with a 2 m by 2 m square cut out of one corner. What is its perimeter, in metres? (Careful — it may surprise you!)

Kofi has 20 m of fence for a rectangular pen. Which pen gives his goats the most grass?

Two angles of a triangle are 47° and 68°. How many degrees is the third angle?

A triangle has angles 90°, 45° and 45°. Which words describe it? Select all that apply.

Musa draws two angles. Both open exactly as wide as the corner of a book. The first has arms 2 cm long; the second has arms 10 cm long. Which angle is bigger?

A box is 5 cm long, 3 cm wide and 4 cm high. How many 1 cm cubes fit exactly inside it? (This is its volume in $\text{cm}^3$.)

In Lean, triangle_angle_sum has the hypotheses straight : d + c + e = 180, alt₁ : d = a and alt₂ : e = b, and concludes a + b + c = 180. Which sentence describes what Lean has checked?

Complete the two functions so that area(w, h) returns the area and perimeter(w, h) returns the perimeter of a rectangle w units wide and h units high. The tests then check Kofi's pens.