Question

a triangle and three semicircles compose a warning label on a sticker. determine the approximate area of the warning label.

Explanation:

Step1: Calculate area of the triangle

The formula for the area of a triangle is $A_{triangle}=\frac{1}{2}\times base\times height$. Here, the base is $10 + 10=20$ cm and the height is $8.7$ cm. So $A_{triangle}=\frac{1}{2}\times20\times8.7 = 87$ $cm^{2}$.

Step2: Calculate area of the three semi - circles

The three semi - circles together form 1.5 full - circles. The radius of each semi - circle is $r = 5$ cm. The formula for the area of a circle is $A=\pi r^{2}$. So the area of 1.5 circles is $A_{circles}=1.5\times\pi\times5^{2}=1.5\times25\pi=37.5\pi\approx37.5\times3.14 = 117.75$ $cm^{2}$.

Step3: Calculate total area of the warning label

The total area $A = A_{triangle}+A_{circles}$. So $A=87 + 117.75=204.75$ $cm^{2}$.

Answer:

$204.75$ $cm^{2}$