Question

the diagram shows a logo made from three circles

each circle has centre O


what percentage of the logo is shaded blue?

Answer 1

Answer:

Use the formula π*(r^2) where r is radius

Area of big circle, all 3=314.1592654 (approximately) and this is =100%

Area of middle circle=153.93804

Area of small circle=78.53981634

Percentage of middle circle with small circle = (153.93804/314.1592654)*100= 48.999999999999 approx= 49%

Percentage of small circle alone = (78.53981634/314.1592654)*100

= 25%

So 51%= big circle alone

And 51%+25%= 76%

100%-76%=24%

Answer 2

Answer:

The percentage of the logo is shaded blue: 24%

Step-by-step explanation:

From the given photo, we can see there are 3 circles.

• The biggest one with its radius: 5+2+3 = 10 cm
• The medium one with its radius: 5+2 = 7 cm
• The smallest one with its radius: 5 cm  

After that, we find the area of each circle with the following formula:

A =π $r^{2}$

• The area of the biggest circle is: π $10^{2}$ =  100π $cm^{2}$
• The area of the medium circle is: π $7^{2}$ = 49π$cm^{2}$
• The area of the smallest circle is: π $5^{2}$ = 25π $cm^{2}$

So the area of the shade part is:

The area of the medium circle - The area of the smallest circle

= 49π$cm^{2}$ - 25π $cm^{2}$

= 24π $cm^{2}$

So the percentage of the logo is shaded blue:

= The area of the shaded blue / The area of the biggest circle

= 24π $cm^{2}$ / 100π $cm^{2}$

= 0.24

= 24%