Circumference 72984

Task 1 - The circumference of the square is 280 mm. What is its area?
Task 2 - the perimeter of the rectangle is 44.6dm, and its width is 6.3dm. Calculate the area of this rectangle.

Correct answer:

S₁ =  49 cm²
S₂ =  100.8 dm²

Step-by-step explanation:

$$\begin{gathered} o_1=280\text{mm}\to \text{cm}=280:10\text{cm}=28\text{cm} \\ {o}_1=4a \\ a=o_1/4=28/4=7\text{cm} \\ {S}_1=a^2=7^2=49{\text{cm}}^2 \end{gathered}$$

$$\begin{gathered} o_2=44.6\text{dm} \\ y=6.3\text{dm} \\ {o}_2=2x+2y \\ x=o_2/2-y=44.6/2-6.3=16\text{dm} \\ {S}_2=x\cdot y=16\cdot 6.3=100.8{\text{dm}}^2 \end{gathered}$$

Try another example