Answer:
15
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtraction Property of Equality<u>
</u>
Step-by-step explanation:
<u>Step 1: Define</u>
<em>Identify</em>
5a - 10b = 45
<em>b</em> = 3
<u>Step 2: Solve for </u><em><u>a</u></em>
- Substitute in <em>b</em> [Equation]: 5a - 10(3) = 45
- Multiply: 5a - 30 = 45
- [Addition Property of Equality] Add 30 on both sides: 5a = 75
- [Division Property of Equality] Divide 5 on both sides: a = 15
Tip: decimal to percentage is easy. 0.78 would be 78%. percentage would be vice versa 39% is 0.39. decimal or percentage to fraction is easy aswell, make the number out of 100, meaning 39% would be 39/100
Big/small=4/7
r1/r2=4/7 where r1, r2 are radius of a big and small circles respectively
r1/3=4/7
r1=12/7
circumference of a big circle is2πr1=2π*12/7=24π/7 cm
