Mark the angles and sides of each pair of triangles to indicate that they are congruent. NO LINKS!!!​

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Explanation:

The order of the lettering is important because the order tells us how the letters pair up.

For DCB and CDJ, we have D and C as the first letters. So that means angle D and angle C are congruent between the triangles. I've marked this in red. The other angles are handled the same way.

The congruences for the segments are then built up from the angles.

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step-by-step explanation:

x = central angle apc = measure of minor arc ac

the two angles x and 30 add to 180, so x+30 = 180 and x = 180-30 = 150. the measure of minor arc ac is 150 degrees.

what we need to do from here is find the circumference and then multiply it by x/360 since there are 360 degrees in a circle. in this case, x = 150, so x/360 = 150/360 = 15/36 = 5/12. the shortest distance along the curve from a to c is 5/12 of the distance around the entire circle (aka circumference)

c = circumference

c = pi*d

c = pi*24

c = 24pi

now multiply this by 5/12 to get

distance along minor arc ac = (5/12)*(circumference)

distance along minor arc ac = (5/12)*(24pi)

distance along minor arc ac = 10pi

the formula you can use is

l = (x/360)*pi*d

with

l = length of minor arc

x = central angle

d = diameter

which essentially is the steps we took though a bit differently.