Area of a Circle
What is the formula for the area of a circle?
A = πr²
What is the formula for the circumference of a circle?
C = 2πr or πd
Find the volume of a cube with side length 5 cm.
5³ = 125 cm³
Find the surface area of a cube with side length 4 in.
6×4² = 6×16 = 96 in²
True or False: Diameter = 2 × radius
True
Find the area of a circle with a radius of 3 cm. Use π ≈ 3.14
28.26 cm²
Find the circumference of a circle with a diameter of 10 cm
31.4 cm
Find the volume: length = 5 in, width = 3 in, height = 4 in.
5×3×4 = 60 in³
What’s the surface area of a cube with side length 3 m
6×3² = 6×9 = 54 m²
A circular rug has a radius of 4 feet. Find the area.
50.24 ft² (π × 4²)
If the diameter of a circle is 12 inches, what is its area?
113.04 in² (r = 6, A = π × 6² = 113.04)
A circular track has a radius of 6 meters. What is its circumference?
37.68 m (2 × 3.14 × 6)
Triangular Prism: Find the volume: base = 6 cm, height of triangle = 4 cm, prism height = 10 cm
½×6×4×10 = 120 cm³
A box is 10 cm long, 4 cm wide, and 6 cm high. What is its surface area?
SA = 2(10×4) + 2(10×6) + 2(4×6) = 80 + 120 + 48 = 248 cm²
What shape results from slicing a cylinder horizontally?
Circle
A circular garden has an area of 78.5 m². What is the radius?
r ≈ 5 m (78.5 = 3.14 × r² → r² = 25)
A circle’s circumference is 62.8 inches. What is its diameter?
20 in (C = πd → 62.8 = 3.14 × d)
A triangular prism has a triangle base of 5 cm and 8 cm, and a prism height of 12 cm
½×5×8×12 = 240 cm³
Surface area of a rectangular prism: l = 7, w = 3, h = 2
SA = 2(7×3 + 7×2 + 3×2) = 2(21+14+6)= 2×41 = 82
What is the circumference of a circle with radius 15 cm?
94.2 cm (2 × 3.14 × 15)
A circle has a radius of 7.5 feet. What is its area in square feet?
176.71 ft² (π × 7.5² = 176.71)
The radius of a circle is 8.75 cm. What is the circumference?
54.95 cm (2π × 8.75)
True or False: The height of the triangle and the height of the prism are the same
False
Multi-step: Find both the volume and surface area of a cube with side 6 cm
V = 216 cm³, SA = 216 cm²
A cone is sliced vertically through its apex. What is the shape of the cross section?
Triangle