Formulas Formulas Formulas appear in almost any profession

Formulas

Formulas • Formulas appear in almost any profession. • A formula is an expression where the variables and result have a specific meaning. • In the formula P=2 w+2 l the w and l are measurements and the result, P, is the perimeter of a rectangle.

Steps: • Copy the pattern the formula makes. • Insert the known numbers for the variables. • Simplify.

Formulas • You don’t need to memorize these formulas. • In fact you may not even need to understand what the formula means. • You do need to be able to put the values in the proper place and simplify.

Formula A=lw • Where w is width and l is length • Example: A=(7)(3) • =21 in 2.

A= ½ h(b 1+b 2) • where h is the perpendicular height between the bases and b 1 and b 2 are the bases. • A= ½ (4)(4+10)=28 in 2.

V=4/3πr 3 • where r is radius and π is pi. • Example: • radius 3 mi • V=4/3π(3)3=36 π • =113. 9 mi 3.

SA= πr 2+πrs • where r is radius, π is pi, and s is the length of the slant of the cone. • Example: • SA= π(5)2+π(5)(13) • = 90π • 282. 74

I=Prt • where I is interest, P is the principal, r is the annual rate, and t is the time in years. • A car is sold for $15000 with simple interest at 12% for a period of 5 years. How much interest is paid? How much total is paid back? What is the monthly payment? • I=Prt=(15000)(. 12)(5)=$9000 (Write 12% as a decimal. ) • Total = 15000+9000=$24000 (Add the principle to the interest. ) • Monthly Pmt. = 240000/12=$400 • (Divide the total by the number of months. )

Celsius to Fahrenheit • What is 80 C in Fahrenheit?

Fahrenheit to Celsius • What is 80 F in Celsius?

Mean or average • Where n is the number of numbers to be averaged and x 1, x 2, x 3 and so on are the numbers to be averaged. • Janet got a 458, 500, 482, 440, and 500 on her GED tests. What was her average score? A=476

Distance • where d is the distance between two points (x 1. y 1) and (x 2, y 2). • Find the distance between (-2, -3) and (8, 3).

Quadratic Formula • The solution for an equation • 0=ax 2 + bx + c the solution is • I know big and hairy.

• What are the solutions for: • 0=2 x 2 -9 x+10 a =2, b=-9 and c=10