This is the symmetric property of equality, and in a more general form it can be written as: if a=b then b=a.
This is not to be confused with communicative property, which says that the order doesn't matter in some operations, such as addition, and can be written as a+b=b+a
Answer:
answer = 3(a +b)
Step-by-step explanation:

Answer:
Check Explanation
Step-by-step explanation:
The amygdala is the brain's emotional center. It is responsible for instinctual thinking and impulse control. It develops during early teenage years and this means the amygdala is not developed to the optimal level during teenage years. This makes teenagers very prone to impulsive behavior.
Also, the prefrontal cortex which is responsible for decision-making skills and the ability to measure risks is not fully developed in the teenage child stage. This is why teenagers make poor decisions and aren't great at measuring risks thereby making riskier choices like using the phone while driving.
These two brain components are fully developed in adults hence, it is less likely for adults to make poor decisions like texting while driving, which is a riskier thing to do than not using a seatbelt.
Again, teenagers have this invincibility feeling where they feel like they are more active and can react faster to road dangers. This deceives them into making such riskier decisions.
The current world also has turned into something else where people (teenagers especially) strive to get the most current news information as they are happening. The need to stay connected to social media is another reason why teenagers can't stay off their phones.
Finally, the fact that public intervention programs and ad campaigns promoting seat-belt use way more than not using cell-phones use while driving also mean more people are more conscious about using seatbelts while driving than not using their cellphones. In recent times, the campaigns, laws and bans on use of phones while driving are just gaining prominence.
In conclusion, the combination of all these factors/reasons is why the percentage of teenage high school students who use phones while driving is way more than the percentage that don't use a seatbelt although texting while driving is arguably much riskier than not wearing a seat belt.
Hope this Helps!!!
Answer:
Part A: See the image attached. The angle between the radius and the chord will always be 90 degree if the radius is perpendicular to the chord
Part B: There are many ways to prove this and here is mine
Prove OC is perpendicular to AB
We know that ΔAEC≅AED by SSS criteria (SSS criteria is when all three sides of a triangle is equal making them congruent)
to prove this that they apply to the SSS criteria:
m∠ADO=m∠BDO
m∠ADO=90°=m∠BDO
Part C: See the image attached. A radius is perpendicular to a chord when the chord is equally divided in half by the radius.
Part D: There are many ways to prove this and here is mine
Prove OC is perpendicular to AB
AO=BO because AO and BO are both radii
OD≅OD by reflexive theorem
ΔADO≅ΔBDO because they are both right triangle with the hypotenuse and a side
AB≅BC means that OC is perpendicular to AB
If you are still confused then I recommend watching these vdos by khan academy about proving perpendicular radius bisector: https://youtu.be/2NgzruZ4_5c
https://youtu.be/TgDk06Qayxw
Hope this helped bye:)