Record and Compare and order lengths of shapes objects in millimetres (mm) and centimetres (cm). Measure your 3D objects in mm and cm using ruler.

• Slant height: $6.1 \text{ cm} = 61 \text{ mm}$. (Correct: $6.1 \times 10 = 61$)
• Height: $3.8 \text{ cm} = 38 \text{ mm}$. (Correct: $3.8 \times 10 = 38$)
• Base side 1: $2.5 \text{ cm} = 25 \text{ mm}$. (Correct: $2.5 \times 10 = 25$)
• Base side 2: $4 \text{ cm} = 40 \text{ mm}$. (Correct: $4 \times 10 = 40$) All measurements for the pyramid are correct.

• Slant height: You have $2.7 \text{ cm}$ and $28 \text{ mm}$. Conversion: $2.7 \text{ cm} \times 10 = 27 \text{ mm}$. Correction: $2.7 \text{ cm}$ is equal to $\mathbf{27 \text{ mm}}$.
• Height: $2.5 \text{ cm} = 25 \text{ mm}$. (Correct: $2.5 \times 10 = 25$)
• Base diameter: $2.4 \text{ cm} = 24 \text{ mm}$. (Correct: $2.4 \times 10 = 24$)

• Height: You have $1.8 \text{ cm}$ and $15 \text{ mm}$. Conversion: $1.8 \text{ cm} \times 10 = 18 \text{ mm}$. Correction: $1.8 \text{ cm}$ is equal to $\mathbf{18 \text{ mm}}$.
• Diameter: $1.4 \text{ cm} = 14 \text{ mm}$. (Correct: $1.4 \times 10 = 14$)
• Additional measurement (possibly radius): You have $1.6 \text{ cm}$ and $8 \text{ mm}$. Conversion: $1.6 \text{ cm} \times 10 = 16 \text{ mm}$. Correction: $1.6 \text{ cm}$ is equal to $\mathbf{16 \text{ mm}}$.

• Length: $4.1 \text{ cm} = 41 \text{ mm}$. (Correct: $4.1 \times 10 = 41$)
• Width: $1.4 \text{ cm} = 14 \text{ mm}$. (Correct: $1.4 \times 10 = 14$) All measurements for the rectangular prism are correct.

The corrected measurements are:

• Cone slant height: $2.7 \text{ cm} = \boxed{\text{27 mm}}$
• Cylinder height: $1.8 \text{ cm} = \boxed{\text{18 mm}}$
• Cylinder additional measurement: $1.6 \text{ cm} = \boxed{\text{16 mm}}$