X+1 is the width of the envelope. If you need work just say do in the comments please.
firstly, I'd like to point out the graph is misleading, if AC is 10 it should be the shorter sides, but it shows as the longer side there.
let's bear in mind that in a rhombus, all sides are equal, even though they may be slanted, the diagonals meet at right-angles always, so the center is simply four 90° angles, and the diagonals bisect each other, namely they cut each other in equal halves.
check the picture below.
Answer:
1st
Step-by-step explanation:
The two triangles are similar by AA
Firstly, we can see that angle LKM and QKR are congruent as they are vertical angles.
The second set can be identified by noticing that RM is a transversal through 2 parrallel lines LM and QR. That manes QRK, and LMK alternate interior angles, showing that the angles are congruent. Hence similarity by AA
Let the cost price of article be x :
x + x × ( 15/100 ) = 2300
x + x × ( 5 × 3 / 5 × 20 ) = 2300
x + x × ( 3 / 20 ) = 2300
x + ( 3 × x / 20 ) = 2300
x + ( 3x / 20 ) = 2300
( 20x / 20 ) + ( 3x / 20 ) = 2300
20x + 3x / 20 = 2300
23x / 20 = 2300
Multiply both sides by 20
( 23x / 20 ) × 20 = 2300 × 20
23x = 2300 × 20
23x = 23 × 2000
Divide both sides 23
23x ÷ 23 = ( 23 × 2000 ) ÷ 23
x = Rs 2000
