Answer:
b² = a² + c² - 2ac cos B
Step-by-step explanation:
The cosine rule can be use when you are given three sides of a triangle and ask to find any angle or when you are given two sides and a included angles(the angle between the two sides given) and ask to find the length of a side.
The equation Sophia can use to solve for the side length(b) of a triangle when given two length and the included angle can be expressed below. Sophia was given two sides and an included angle and was asked to find a side length b.
For sides a, b and c the cosine rule can be represented below
a² = b² + c² - 2bc cos A
b² = a² + c² - 2ac cos B
c² = a² + b² - 2ab cos C
The equation required base on your question is
b² = a² + c² - 2ac cos B
steps
(x) = 5x^2-3x+7
refine
x=5x^2-3x+7
Switch sides
5x^2-3x+7-x=x-x
Subtract x from both sides
5x^2-4x+7=0
Solve with the quadratic formula
Answer:
$7724
Step-by-step explanation:
Her estimated quarterly income is $73,040/4 = $18,260.
Her estimated tax rate is ...
27% + 12.4% + 2.9% = 42.3%
This tax rate applied to her estimated earnings gives an estimated quarterly tax of ...
$18,260 × 0.423 = $7723.98
≈ $7724 . . . . . taxes are rounded to the nearest dollar
