How to estimate sums and differences

Hello from MrBillDoesMath!

example estimates: 1.3, 1.4

Discussion:

According to the question author  we need to estimate sum of

9/10 + 7/16

The question is how good an estimate is needed! For example, here's a quick, but hardly accurate, estimate:

9/10 + 7/16 is approx  9/10 + 8/16 = 9/10 + 1/2 = 9/10 + 5/10 = 14/10 = 1.4

Here's a more accurate estimate:

9/10 + 7/16 =  (9*8)/80 +     (7*5)/ 80 =

                 (72 + 35)/80 =

                 107/80  = which is about 1.3

Thank you,

MrB

18 units²

step-by-step explanation:

first let's find altitude bd using the distance formula

d = √((y₂ - y₁)² + (x₂ - x₁)²)

bd = √((0 - -3)² + (0 - 3)²)

bd = √18

given the placement of points a and c, we can denote that point d bisects segment ac.

we will call ac the base.

using the distance formula

ac = √((0 - 6)² + (-6 - 0)²)

ac = √72

knowing our base and our height, we can plug these into our triangle area formula

area = (b * h)/2

area = (√18 * √72) / 2

area = (√1296) / 2

area = 36 / 2

area = 18 units²