Respuesta :

In this case, we'll have to carry out several steps to find the solution.

Step 01:

Data:

equilateral triangle:

side = 7x

circle:

radius = 4r

Step 02:

area:

a = circle area - triangle area

triagle area:

triagle area = (b * h) / 2

b = 7x

h:

[tex]\begin{gathered} (7x)^2=h^2+(\frac{7x}{2})^2 \\ 49x^2=h^2+\frac{49x^2}{4} \\ h^2=49x^2-\frac{49x^2}{4}=\frac{147x^2}{4} \\ h\text{ = }\sqrt[]{\frac{147x^2}{4}\text{ }}=6.06x=6.1x \end{gathered}[/tex]

h = 6.1x

[tex]\text{triangle area = }\frac{7x\cdot6.1x}{2}=\frac{42.7x^2}{2}=21.35x^2[/tex]

circle area:

circle area (r) = π r² = π (4r)² = 16 π r²

a = circle area - triangle area

a = 16 π r² - 21.35x²

The answer is:

a = 16 π r² - 21.35x²