Answer:
The radii of the circles are 12 cm and 7cm.
Step-by-step explanation:
Let the radii of the circles be 
Given:
Sum of circumference of two circles= 38π cm
Formula for circumference of a circle with radius r = 2πr
------------1
Sum of areas of two circles= 193π cm²
Area of circle with radius r = πr²
-------2
Substituting r2 = 19 - r1 in equation 2 we get:

Then r2 = 19 - r1

I am not sure what this answer is
D because i did this alreadyyy
The missing piece of information in the proof is that m∠DOA and m∠BOC are vertical opposite angles.
<h3>How to find vertically opposite angles?</h3>
We want to prove that m∠BOC = 90°.
We are given that m∠AOB is a right angle triangle. Thus;
m∠BOC must also be equal to 90°
Now, since m∠BOC and m∠AOB are right angles, then it means that we must equally say that m∠DOA and m∠BOC are vertical opposite angles and they are as such equal.
Thus, the missing piece of information in the proof is that m∠DOA and m∠BOC are vertical opposite angles.
Read more about vertical opposite angles at; brainly.com/question/24425517
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1 Simplify a-3a+5a−3a+5 to -2a+5−2a+5
-2a+5-(-a+2b+3)−2a+5−(−a+2b+3)
2 Simplify brackets
-2a+5+a-2b-3−2a+5+a−2b−3
3 Gather like terms
(-2a+a)+5-2b-3(−2a+a)+5−2b−3
4 Simplify
-a+5-2b-3−a+5−2b−3
5 Simplify
-a-2b+2−a−2b+2