Priya drew a circle whose area is 25 cm. Dan drew a circle whose diameter is 4 times the radius of Priya's circle. How many times greater is the area of Dan's
circle?

Respuesta :

Answer:

400

Step-by-step explanation:

first work out the radius of priya's circle with the equation a = [tex]\pi r^{2}[/tex]

[tex]25 = \pi r^{2}[/tex]

[tex]\frac{25}{\pi } = r^{2}[/tex]

[tex]r = \sqrt{\frac{25}{\pi } }[/tex]

we know the diameter of a circle is 2 times the radius so the diameter of priya's circle is 2x[tex]\sqrt{\frac{25}{\pi } }[/tex]

this means that if the diameter of dan's circle is 4 times bigger it must be

8x[tex]\sqrt{\frac{25}{\pi } }[/tex]

to find the radius of dan's circle we divide the diameter by to 2 to give

4x [tex]\sqrt{\frac{25}{\pi } }[/tex]

then use the a=[tex]\pi r^{2}[/tex] equation again

[tex]a= (4 \sqrt{\frac{25}{\pi } })^{2} \pi[/tex]

which equals 400

hope that helped