Diameter of the circle is BD as shown, as indicated and passed through center where BD passes, triangle ABD is a right triangle with angle ABD as the right angle. It means ADB and ABD are complementary which means
AB = 140 degree
AD=40 degree
A petri dish is simply a circle; thus, we use the formula of the area of the circle which is <span>πr^2.
Given r = 40 mm
A = </span>π(40)^2 = <span>5026.55 sq. mm
</span>
Population density = bacteria count / area
PD = 2,100 / <span>5026.55
PD = </span><span>0.417782 bacteria / mm sq.
Therefore, the answer is approximately 0.418 </span><span>bacteria per square millimeter.</span>
Answer:
E. Step 3
Step-by-step explanation:
Step 2:
2x + 18 = 4x + <u>28 + 2</u>
Step 3:
2x + 18 = 4x + <u>26</u>
She subtracted instead of adding (see bold and underline)
