What is the radius of a circle whose area is equal to the sum of the areas of two circles whose radii are 20cm & 21cm?

5cm

Step-by-step explanation:

29

Step-by-step explanation:

20^2 times 3.14= 1256

21^2 times 3.14= 1384.74

the sum of those two is 2640.74

the square root of that is 29

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.