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Area Day 2. Math 10-3 Ch. 3 Measurement. Ex1. Determine the area of the following shape. *First, find the formula for the area of a TRIANGLE: Area triangle = b x h Fill in the formula with the information from the diagram. A Tri = x 8 ft x 3 ft
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Area Day 2 Math 10-3 Ch. 3 Measurement
Ex1. Determine the area of the following shape. • *First, find the formula for the area of a TRIANGLE: Area triangle = b x h • Fill in the formula with the information from the diagram. • ATri = x 8 ft x 3 ft • Now solve. *remember, multiplying by is the same as dividing by 2! • 8 x 3 2 = 12 ft2
Ex2. Determine the area of the following shape. • *First, find the formula for the area of a PARALLELOGRAM: Area Parallelogram = b x h • Fill in the formula with information from the diagram: • Ap = b x h = 12 cm x 7 cm = 84 cm2
Ex3. Determine the area of the following shape. • First, find the formula for the area of a TRAPEZOID: Area Trapezoid = (b1+b2) x h • Fill in the formula with information from the diagram: • ATrap = (9 mm + 4 mm) x 3 mm • *First, you must add (9 + 4) because they are in BRACKETS. Remember BEDMAS? • 9 + 4 = 13 13 x 3 2 = 19.5 mm2
Ex4. The area of a triangle is 12 in2. If the base of the triangle is 6 in long, what is the height of the triangle? • ATriangle = 12 in2 b = 6 in h = ? • We are looking for the height! • Fill in the formula for area of a triangle with what we already know: • ATriangle = b x h • 12 in2 = 6 in x h 2 • What is the opposite of dividing by 2? Multiply by 2 on the other side! • 12 x 2 = 6 x h • 24 = 6 x h
Ex4. The area of a triangle is 12 in2. If the base of the triangle is 6 in long, what is the height of the triangle? • 24 = 6 x h • What is opposite of multiplying by 6? Divide by 6 on the other side! • 24 6 = h • h = 4 in • Double check to make sure: • ATriangle = b x h = 6 x 4 2 = 12 in2
Ex5. The area of a square is 16 cm2. What is the length of one side? • Fill in the formula for area of a square with what we already know: • ASquare = s2 • 16 cm2 = s2 • But we don’t want s2 we want justs ! • What is the opposite of squaring something? Square rooting!
Find the button on your calculator. This is the operation you use to “un-square” a number. • 16 = s2 • = s • s = 4 cm • Double check to make sure: • Asquare = s2 = s x s = 4 x 4 = 16 cm2
How do we convert between SI square units? • Remember, the SI measuring system is based on 10.
Ex6. 8 m2 is how many cm2? • HAVE m2 WANT cm2 • Start at m2 and follow the arrows to cm2 we have to multiply by 102 twice! • *Remember 102 is the same as 10 x 10 ! • 8m2 x 102 x 102 = 8 m2 x 10 x 10 x 10 x 10 = 80000 cm2
Ex7. 350 mm2 is how many dm2? • HAVE mm2 WANT dm2 • Start at mm2 and follow the arrows to dm2 we have to divide by 102 twice! • 350mm2 102 102 = 350 10 10 10 10 = 0.035 dm2
How do we convert between Imperial square units? • Remember, the Imperial Measurement System is based on referents!
Ex8. 9 yd2 is how many in2? • HAVE ft2 WANT in2 • Start at yd2 and follow the arrows to in2 We have to x 32 and then 122! • 9 yd2 x 32 x 122 = 9 yd2 x 3 x 3 x 12 x 12 = 11664 in2
Ex9. 2 016 in2 is how many ft2 ? • HAVE in2 WANT ft2 • Start at in2 and follow the arrows to ft2 We have to divide by 122! • 2016 in2 122 = 2 016 12 12 = 14 ft2