1. Is 2/12 = 5/28 a true proportion? Step 1. Cross multiply.

2 x 28 = 12 x 56
56 = 672

Step 2. is the proportion true?

, because the cross products are not .

The proportion true, because 2/12 and 5/28 equivalent ratios.

Cross multiply:

⇒ 2 x 28 = 5 x 12

⇒ 56 = 60

Is this proportion true?

No, because the cross products are not equal.

The proportion is not true, because 2/12 and 5/28 are not equivalent ratios.

The answer is in the image 

The total nom of  code that can be used is equal to 5+3 = 8

The answer is in the image 

y=2x+15

where y=Value of coin

x=Age in years

Value of coin after 19 years=2*19+15

=$53

Therefore, Value after 19 years=$53

Here,

tip=18%of $32

tip=(18/100)*32

=0.18*32

=$5.76

Total payment=32+5.76=$37.76

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

tip=18% of 75.45

     =18/100 * 75.45 = $13.581

Tip = $13.581

Area of rectangle= L*b

here,

L=12.4 cm

b= 8.8 cm

A= L*b

= 12.4 * 8.8 = 109.12 cm^2