Question

bell: unit 1: geometry basics homework 1.6: area of plane figures directions: find the area of each figure. round to the nearest hundredth where necessary. this is a 2 - page document *

Explanation:

Step1: Recall area formulas

For trapezoid: $A=\frac{(a + b)h}{2}$, triangle: $A=\frac{1}{2}bh$, square: $A = s^2$, circle: $A=\pi r^2$ (semicircle: $A=\frac{1}{2}\pi r^2$)

Step2: Solve for problem 1

Trapezoid with $a = 21m$, $b=32m$, $h = 21m$. $A=\frac{(21 + 32)\times21}{2}=\frac{53\times21}{2}=\frac{1113}{2}=556.5m^2$

Step3: Solve for problem 2

Trapezoid with $a = 7in$, $b = 11in$, $h=4in$. $A=\frac{(7 + 11)\times4}{2}=\frac{18\times4}{2}=36in^2$

Step4: Solve for problem 3

Circle with $r = 2.9ft$. $A=\pi r^2=\pi\times(2.9)^2\approx3.14\times8.41 = 26.4074ft^2\approx26.4ft^2$

Step5: Solve for problem 4

Triangle with $b = 16cm$, $h = 22cm$. $A=\frac{1}{2}\times16\times22=176cm^2$

Step6: Solve for problem 6

Square with $s = 17.6mm$. $A=s^2=(17.6)^2 = 309.76mm^2$

Step7: Solve for problem 8

Semicircle with $r = 4in$. $A=\frac{1}{2}\pi r^2=\frac{1}{2}\times\pi\times4^2=\frac{1}{2}\times3.14\times16 = 25.12in^2$

Step8: Solve for problem 10

Triangle with $b = 20.4in$, $h = 14.6in$. $A=\frac{1}{2}\times20.4\times14.6=149.88in^2$

Answer:

1. $556.5m^2$
2. $36in^2$
3. $26.4ft^2$
4. $176cm^2$
5. $309.76mm^2$
6. $25.12in^2$
7. $149.88in^2$